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Sample records for 2-arachidonoyl glycerol 2-ag

  1. The inhibition of 2-arachidonoyl-glycerol (2-AG) biosynthesis, rather than enhancing striatal damage, protects striatal neurons from malonate-induced death: a potential role of cyclooxygenase-2-dependent metabolism of 2-AG.

    PubMed

    Valdeolivas, S; Pazos, M R; Bisogno, T; Piscitelli, F; Iannotti, F A; Allarà, M; Sagredo, O; Di Marzo, V; Fernández-Ruiz, J

    2013-10-17

    The cannabinoid CB2 receptor, which is activated by the endocannabinoid 2-arachidonoyl-glycerol (2-AG), protects striatal neurons from apoptotic death caused by the local administration of malonate, a rat model of Huntington's disease (HD). In the present study, we investigated whether endocannabinoids provide tonic neuroprotection in this HD model, by examining the effect of O-3841, an inhibitor of diacylglycerol lipases, the enzymes that catalyse 2-AG biosynthesis, and JZL184 or OMDM169, two inhibitors of 2-AG inactivation by monoacylglycerol lipase (MAGL). The inhibitors were injected in rats with the striatum lesioned with malonate, and several biochemical and morphological parameters were measured in this brain area. Similar experiments were also conducted in vitro in cultured M-213 cells, which have the phenotypic characteristics of striatal neurons. O-3841 produced a significant reduction in the striatal levels of 2-AG in animals lesioned with malonate. However, surprisingly, the inhibitor attenuated malonate-induced GABA and BDNF deficiencies and the reduction in Nissl staining, as well as the increase in GFAP immunostaining. In contrast, JZL184 exacerbated malonate-induced striatal damage. Cyclooxygenase-2 (COX-2) was induced in the striatum 24 h after the lesion simultaneously with other pro-inflammatory responses. The COX-2-derived 2-AG metabolite, prostaglandin E2 glyceryl ester (PGE2-G), exacerbated neurotoxicity, and this effect was antagonized by the blockade of PGE2-G action with AGN220675. In M-213 cells exposed to malonate, in which COX-2 was also upregulated, JZL184 worsened neurotoxicity, and this effect was attenuated by the COX-2 inhibitor celecoxib or AGN220675. OMDM169 also worsened neurotoxicity and produced measurable levels of PGE2-G. In conclusion, the inhibition of 2-AG biosynthesis is neuroprotective in rats lesioned with malonate, possibly through the counteraction of the formation of pro-neuroinflammatory PGE2-G, formed from COX-2

  2. Regulation of inflammation by cannabinoids, the endocannabinoids 2-arachidonoyl-glycerol and arachidonoyl-ethanolamide, and their metabolites.

    PubMed

    Turcotte, Caroline; Chouinard, François; Lefebvre, Julie S; Flamand, Nicolas

    2015-06-01

    2-Arachidonoyl-glycerol (2-AG) and arachidonyl-ethanolamide (AEA) are endocannabinoids that have been implicated in many physiologic disorders, including obesity, metabolic syndromes, hepatic diseases, pain, neurologic disorders, and inflammation. Their immunomodulatory effects are numerous and are not always mediated by cannabinoid receptors, reflecting the presence of an arachidonic acid (AA) molecule in their structure, the latter being the precursor of numerous bioactive lipids that are pro- or anti-inflammatory. 2-AG and AEA can thus serve as a source of AA but can also be metabolized by most eicosanoid biosynthetic enzymes, yielding additional lipids. In this regard, enhancing endocannabinoid levels by using endocannabinoid hydrolysis inhibitors is likely to augment the levels of these lipids that could regulate inflammatory cell functions. This review summarizes the metabolic pathways involved in the biosynthesis and metabolism of AEA and 2-AG, as well as the biologic effects of the 2-AG and AEA lipidomes in the regulation of inflammation.

  3. 2-Arachidonoyl glycerol sensitizes the pars distalis and enhances forskolin-stimulated prolactin secretion in Syrian hamsters.

    PubMed

    Yasuo, Shinobu; Fischer, Claudia; Bojunga, Joerg; Iigo, Masayuki; Korf, Horst-Werner

    2014-04-01

    2-Arachidonoyl glycerol (2-AG) is a major endocannabinoid and an important regulator of neuroendocrine system. In Syrian hamster and human, we found that 2-AG is synthesized in the hypophysial pars tuberalis (PT), an interface between photoperiodic melatonin signals and neuroendocrine output pathways. The target of 2-AG produced in the PT is likely to be the pars distalis (PD). Here we demonstrate that 2-AG in combination with forskolin stimulated prolactin secretion from PD organ cultures of Syrian hamsters, whereas incubation with 2-AG alone had no effect. Forskolin-induced prolactin secretion was also significantly enhanced when cultured PD tissue was preincubated with 2-AG. The stimulatory effects of 2-AG on prolactin secretion were blocked by AM251, a selective CB1 antagonist, and were still observed in the presence of quinpirole, a D2-class dopamine receptor agonist. 2-AG also enhanced prolactin secretion in the presence of adenosine, while it had little effect when applied together with adenosine diphosphate (ADP) and adenosine triphosphate (ATP). Moreover, the effect of forskolin was mimicked by adenosine in a dose-dependent manner. In conclusion, our data suggest that 2-AG sensitizes the PD tissue to potentiate the stimulating effects of forskolin and adenosine on prolactin secretion and thus provide novel insight into the mode of action of 2-AG in the PD.

  4. The direct actions of cannabidiol and 2-arachidonoyl glycerol at GABAA receptors.

    PubMed

    Bakas, T; van Nieuwenhuijzen, P S; Devenish, S O; McGregor, I S; Arnold, J C; Chebib, M

    2017-02-27

    Cannabidiol (CBD) is a major non-intoxicating component of cannabis and possesses anti-epileptic, anxiolytic and anti-hyperalgesic properties. The mechanism of action of CBD in producing such effects remains unclear. Despite evidence that some endogenous and synthetic cannabinoids interact with GABAA receptors, no-one has yet investigated the effects of CBD. Here we used two-electrode voltage clamp electrophysiology to compare the actions of CBD with those of the major central endocannabinoid, 2-arachidonoyl glycerol (2-AG) on human recombinant GABAA receptors (synaptic α1-6βγ2 and extrasynaptic α4β2δ) expressed on Xenopus oocytes. CBD and 2-AG were positive allosteric modulators at α1-6βγ2 receptors, with low micromolar potencies. The maximal level of enhancement seen with either CBD or 2-AG were on α2-containing GABAA receptor subtypes, with approximately a 4-fold enhancement of the GABA EC5 evoked current, more than twice the potentiation seen with other α-subunit receptor combinations. Further we observed β-subunit selectivity, whereby modulatory activity was higher at β2/β3 over β1 subunits. The β1-subunit homologous mutant β2(V436T) substantially diminished the efficacy of both drugs to a third of that obtained with wild-type β2 subunit combinations, but without changing potency. The potency of CBD increased and efficacy preserved in binary α1/α2β2 receptors indicating that their effects do not involve the classic benzodiazepine site. Exploration of extrasynaptic α4β2δ receptors revealed that both compounds enhanced GABA EC5 evoked currents at concentrations ranging from 0.01-1μM. Taken together these results reveal a mode of action of CBD on specifically configured GABAA receptors that may be relevant to the anticonvulsant and anxiolytic effects of the compound.

  5. Bidirectional roles of the brain 2-arachidonoyl-sn-glycerol in the centrally administered vasopressin-induced adrenomedullary outflow in rats.

    PubMed

    Shimizu, Takahiro; Yokotani, Kunihiko

    2008-03-17

    Previously, we reported that intracerebroventricularly (i.c.v.) administered arginine-vasopressin evokes the secretion of noradrenaline and adrenaline from adrenal medulla through the brain phospholipase C- and diacylglycerol-mediated and cyclooxygenase-mediated mechanisms in rats. Diacylglycerol can be hydrolyzed by diacylglycerol lipase to 2-arachidonoyl-sn-glycerol, which may be further degradated by monoacylglycerol lipase to free arachidonic acid, a representative substrate of cyclooxygenase. Recently, 2-arachidonoyl-sn-glycerol has been recognized as a major endocannabinoid, which can modulate synaptic transmission in the brain. In the present experiment, therefore, we examined (1) a role of the brain 2-arachidonoyl-sn-glycerol as a precursor of arachidonic acid in the centrally administered vasopressin-induced elevation of plasma noradrenaline and adrenaline, and (2) a regulatory role of the brain 2-arachidonoyl-sn-glycerol as an endocannabinoid on the vasopressin-induced response, using urethane-anesthetized rats. The vasopressin (0.2 nmol/animal, i.c.v.)-induced elevation of plasma catecholamines was reduced by RHC-80267 (diacylglycerol lipase inhibitor) (1.3 and 2.6 micromol/animal, i.c.v.) and also reduced by MAFP (monoacylglycerol lipase inhibitor) (0.7 and 1.4 micromol/animal, i.c.v.). MAFP (1.4 micromol/animal, i.c.v.) also attenuated the 2-arachidonoyl-sn-glycerol (0.5 micromol/animal, i.c.v.)-induced elevation of plasma catecholamines. AM 251 (cannabinoid CB(1) receptor antagonist) (90 and 180 nmol/animal, i.c.v.) potentiated the vasopressin (0.2 nmol/animal, i.c.v.)-induced response, while AM 630 (cannabinoid CB(2) receptor antagonist) (198 and 793 nmol/animal, i.c.v.) was largely ineffective. In addition, WIN 55212-2 (cannabinoid CB receptor agonist) (188 and 470 nmol/animal, i.c.v.) dose-dependently reduced the vasopressin-induced response. These results suggest that the brain 2-arachidonoyl-sn-glycerol generated from diacylglycerol plays a role

  6. Cross-validated stable-isotope dilution GC-MS and LC-MS/MS assays for monoacylglycerol lipase (MAGL) activity by measuring arachidonic acid released from the endocannabinoid 2-arachidonoyl glycerol.

    PubMed

    Kayacelebi, Arslan Arinc; Schauerte, Celina; Kling, Katharina; Herbers, Jan; Beckmann, Bibiana; Engeli, Stefan; Jordan, Jens; Zoerner, Alexander A; Tsikas, Dimitrios

    2017-03-15

    2-Arachidonoyl glycerol (2AG) is an endocannabinoid that activates cannabinoid (CB) receptors CB1 and CB2. Monoacylglycerol lipase (MAGL) inactivates 2AG through hydrolysis to arachidonic acid (AA) and glycerol, thus modulating the activity at CB receptors. In the brain, AA released from 2AG by the action of MAGL serves as a substrate for cyclooxygenases which produce pro-inflammatory prostaglandins. Here we report stable-isotope GC-MS and LC-MS/MS assays for the reliable measurement of MAGL activity. The assays utilize deuterium-labeled 2AG (d8-2AG; 10μM) as the MAGL substrate and measure deuterium-labeled AA (d8-AA; range 0-1μM) as the MAGL product. Unlabelled AA (d0-AA, 1μM) serves as the internal standard. d8-AA and d0-AA are extracted from the aqueous buffered incubation mixtures by ethyl acetate. Upon solvent evaporation the residue is reconstituted in the mobile phase prior to LC-MS/MS analysis or in anhydrous acetonitrile for GC-MS analysis. LC-MS/MS analysis is performed in the negative electrospray ionization mode by selected-reaction monitoring the mass transitions [M-H](-)→[M-H - CO2](-), i.e., m/z 311→m/z 267 for d8-AA and m/z 303→m/z 259 for d0-AA. Prior to GC-MS analysis d8-AA and d0-AA were converted to their pentafluorobenzyl (PFB) esters by means of PFB-Br. GC-MS analysis is performed in the electron-capture negative-ion chemical ionization mode by selected-ion monitoring the ions [M-PFB](-), i.e., m/z 311 for d8-AA and m/z 303 for d0-AA. The GC-MS and LC-MS/MS assays were cross-validated. Linear regression analysis between the concentration (range, 0-1μM) of d8-AA measured by LC-MS/MS (y) and that by GC-MS (x) revealed a straight line (r(2)=0.9848) with the regression equation y=0.003+0.898x, indicating a good agreement. In dog liver, we detected MAGL activity that was inhibitable by the MAGL inhibitor JZL-184. Exogenous eicosatetraynoic acid is suitable as internal standard for the quantitative determination of d8-AA produced from d8-2

  7. Elevation of 2-AG by monoacylglycerol lipase inhibition in the visceral insular cortex interferes with anticipatory nausea in a rat model.

    PubMed

    Limebeer, Cheryl L; Rock, Erin M; Puvanenthirarajah, Nirushan; Niphakis, Micah J; Cravatt, Benjamin F; Parker, Linda A

    2016-04-01

    Anticipatory nausea (AN) is a conditioned nausea reaction experienced by chemotherapy patients upon returning to the clinic. Currently, there are no specific treatments for this phenomenon, with the classic antiemetic treatments (e.g., ondansetron) providing no relief. The rat model of AN, contextually elicited conditioned gaping reactions in rats, provides a tool for assessing potential treatments for this difficult to treat disorder. Systemically administered drugs which elevate the endocannabinoids, anandamide (AEA) and 2-arachidonoyl glycerol (2-AG), by interfering with their respective degrading enzymes, fatty acid amide hydrolase (FAAH) and monoacyl glycerol lipase (MAGL) interfere with AN in the rat model. We have shown that MAGL inhibition within the visceral insular cortex (VIC) interferes with acute nausea in the gaping model (Sticht et al., 2015). Here we report that bilateral infusion of the MAGL inhibitor, MJN110 (but neither the FAAH inhibitor, PF3845, nor ondansetron) into the VIC suppressed contextually elicited conditioned gaping, and this effect was reversed by coadministration of the CB1 antagonist, AM251. These findings suggest that 2-AG within the VIC plays a critical role in the regulation of both acute nausea and AN. Because there are currently no specific therapeutics for chemotherapy patients that develop anticipatory nausea, MAGL inhibition by MJN110 may be a candidate treatment. (PsycINFO Database Record

  8. The antinociceptive triterpene β-amyrin inhibits 2-arachidonoylglycerol (2-AG) hydrolysis without directly targeting cannabinoid receptors

    PubMed Central

    Chicca, A; Marazzi, J; Gertsch, J

    2012-01-01

    BACKGROUND AND PURPOSE Pharmacological activation of cannabinoid CB1 and CB2 receptors is a therapeutic strategy to treat chronic and inflammatory pain. It was recently reported that a mixture of natural triterpenes α- and β-amyrin bound selectively to CB1 receptors with a subnanomolar Ki value (133 pM). Orally administered α/β-amyrin inhibited inflammatory and persistent neuropathic pain in mice through both CB1 and CB2 receptors. Here, we investigated effects of amyrins on the major components of the endocannabinoid system. EXPERIMENTAL APPROACH We measured CB receptor binding interactions of α- and β-amyrin in validated binding assays using hCB1 and hCB2 transfected CHO-K1 cells. Effects on endocannabinoid transport in U937 cells and breakdown using homogenates of BV2 cells and pig brain, as well as purified enzymes, were also studied. KEY RESULTS There was no binding of either α- or β-amyrin to hCB receptors in our assays (Ki > 10 µM). The triterpene β-amyrin potently inhibited 2-arachidonoyl glycerol (2-AG) hydrolysis in pig brain homogenates, but not that of anandamide. Although β-amyrin only weakly inhibited purified human monoacylglycerol lipase (MAGL), it also inhibited α,β-hydrolases and more potently inhibited 2-AG breakdown than α-amyrin and the MAGL inhibitor pristimerin in BV2 cell and pig brain homogenates. CONCLUSIONS AND IMPLICATIONS We propose that β-amyrin exerts its analgesic and anti-inflammatory pharmacological effects via indirect cannabimimetic mechanisms by inhibiting the degradation of the endocannabinoid 2-AG without interacting directly with CB receptors. Triterpenoids appear to offer a very broad and largely unexplored scaffold for inhibitors of the enzymic degradation of 2-AG. LINKED ARTICLES This article is part of a themed section on Cannabinoids. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.167.issue-8 PMID:22646533

  9. Evaluation of oxidation and glyco-oxidation of 1-palmitoyl-2-arachidonoyl-phosphatidylserine by LC-MS/MS.

    PubMed

    Maciel, Elisabete; Faria, Renata; Santinha, Deolinda; Domingues, M Rosário M; Domingues, Pedro

    2013-06-15

    Phosphatidylserine (PS) is an aminophospholipid found mainly in the plasma membranes of all mammalians cells, playing important roles in biological processes such as apoptosis and cell signaling. Due to the presence of a free amine group, under hyperglycemic conditions, PS can undergo glycation reaction, which may increase the susceptibility to oxidation. However, far too little attention has been paid to glycation and oxidation of PS. In this work we studied the oxidation, glycation and glyco-oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phospho-l-serine (PAPS). PAPS and glycated PAPS were oxidized through a Fenton reaction and the oxidation products were monitored by ESI-MS in negative mode. Also, we developed a new sensitive liquid chromatography method coupled with tandem mass spectrometry (LC-MS/MS) to provide a complete profile of oxidized and glyco-oxidized PS. We were able to separate and identify several oxidation products of PAPS and glycated PAPS with modifications in unsaturated fatty acyl chain as long chain oxidation product (hydroxy and mono to tetra-hydroperoxy derivatives), and short chain products with a shortened fatty acyl chain with C5 and C8 length and aldehyde or carboxylic terminal. We have also observed oxidation products arising from structural changes in the serine polar head, which lead to oxidation products with an acetic acid terminal (glycerophosphoacetic acid derivatives) and lysoPS species. Oxidation of glycated PAPS gave rise to several products involving oxidative cleavages of the glucose moiety, mainly between C1 and C2 of the sugar unit. These oxidation products with different polar head groups have shown distinct neutral loss fragmentation patterns. Simultaneous oxidative modifications of the polar head and the fatty acyl chains were also observed. The findings from this study contribute to an ongoing effort to detect PS oxidation and glyco-oxidation products in biological systems.

  10. Short-term exposure to alcohol in rats affects brain levels of anandamide, other N-acylethanolamines and 2-arachidonoyl-glycerol.

    PubMed

    Rubio, Marina; McHugh, Douglas; Fernández-Ruiz, Javier; Bradshaw, Heather; Walker, J Michael

    2007-06-29

    Chronic alcohol exposure leads to significant changes in the levels of endocannabinoids and their receptors in the brains of humans and laboratory animals, as well as in cultured neuronal cells. However, little is known about the effects of short-term periods of alcohol exposure. In the present study, we examined the changes in endocannabinoid levels (anandamide and 2-arachidonoylglycerol), as well as four additional N-acylethanolamines, in four brain regions of rats exposed to alcohol through the liquid diet for a period of 24h. The levels of N-acylethanolamines were diminished 24h after the onset of alcohol exposure. This was particularly evident for anandamide in the hypothalamus, amygdala and caudate-putamen, for N-palmitoylethanolamine in the caudate-putamen, for N-oleoylethanolamine in the hypothalamus, caudate-putamen and prefrontal cortex, and for N-stearoylethanolamine in the amygdala. The only exception was N-linoleoylethanolamine for which the levels increased in the amygdala after the exposure to alcohol. The levels of the other major endocannabinoid, 2-arachidonoylglycerol, were also reduced with marked effects in the prefrontal cortex. These results support the notion that short-term alcohol exposure reduces endocannabinoid levels in the brain accompanied by a reduction in several related N-acylethanolamines.

  11. Development and Pharmacological Characterization of Selective Blockers of 2-Arachidonoyl Glycerol Degradation with Efficacy in Rodent Models of Multiple Sclerosis and Pain.

    PubMed

    Brindisi, Margherita; Maramai, Samuele; Gemma, Sandra; Brogi, Simone; Grillo, Alessandro; Di Cesare Mannelli, Lorenzo; Gabellieri, Emanuele; Lamponi, Stefania; Saponara, Simona; Gorelli, Beatrice; Tedesco, Daniele; Bonfiglio, Tommaso; Landry, Christophe; Jung, Kwang-Mook; Armirotti, Andrea; Luongo, Livio; Ligresti, Alessia; Piscitelli, Fabiana; Bertucci, Carlo; Dehouck, Marie-Pierre; Campiani, Giuseppe; Maione, Sabatino; Ghelardini, Carla; Pittaluga, Anna; Piomelli, Daniele; Di Marzo, Vincenzo; Butini, Stefania

    2016-03-24

    We report the discovery of compound 4a, a potent β-lactam-based monoacylglycerol lipase (MGL) inhibitor characterized by an irreversible and stereoselective mechanism of action, high membrane permeability, high brain penetration evaluated using a human in vitro blood-brain barrier model, high selectivity in binding and affinity-based proteomic profiling assays, and low in vitro toxicity. Mode-of-action studies demonstrate that 4a, by blocking MGL, increases 2-arachidonoylglycerol and behaves as a cannabinoid (CB1/CB2) receptor indirect agonist. Administration of 4a in mice suffering from experimental autoimmune encephalitis ameliorates the severity of the clinical symptoms in a CB1/CB2-dependent manner. Moreover, 4a produced analgesic effects in a rodent model of acute inflammatory pain, which was antagonized by CB1 and CB2 receptor antagonists/inverse agonists. 4a also relieves the neuropathic hypersensitivity induced by oxaliplatin. Given these evidence, 4a, as MGL selective inhibitor, could represent a valuable lead for the future development of therapeutic options for multiple sclerosis and chronic pain.

  12. Enzymatic production of glycerol acetate from glycerol.

    PubMed

    Oh, Seokhyeon; Park, Chulhwan

    2015-02-01

    In this study, we report the enzymatic production of glycerol acetate from glycerol and methyl acetate. Lipases are essential for the catalysis of this reaction. To find the optimum conditions for glycerol acetate production, sequential experiments were designed. Type of lipase, lipase concentration, molar ratio of reactants, reaction temperature and solvents were investigated for the optimum conversion of glycerol to glycerol acetate. As the result of lipase screening, Novozym 435 (Immobilized Candida antarctica lipase B) was turned out to be the optimal lipase for the reaction. Under the optimal conditions (2.5 g/L of Novozym 435, 1:40 molar ratio of glycerol to methyl acetate, 40 °C and tert-butanol as the solvent), glycerol acetate production was achieved in 95.00% conversion.

  13. Glycerol combustion and emissions

    EPA Science Inventory

    With the growing capacity in biodiesel production and the resulting glut of the glycerol by-product, there is increasing interest in finding alternative uses for crude glycerol. One option may be to burn it locally for combined process heat and power, replacing fossil fuels and i...

  14. Glycerol-induced hyperhydration

    NASA Technical Reports Server (NTRS)

    Riedesel, Marvin L.; Lyons, Timothy P.; Mcnamara, M. Colleen

    1991-01-01

    Maintenance of euhydration is essential for maximum work performance. Environments which induce hypohydration reduce plasma volume and cardiovascular performance progressively declines as does work capacity. Hyperhydration prior to exposure to dehydrating environments appears to be a potential countermeasure to the debilitating effects of hypohydration. The extravascular fluid space, being the largest fluid compartment in the body, is the most logical space by which significant hyperhydration can be accomplished. Volume and osmotic receptors in the vascular space result in physiological responses which counteract hyperhydration. Our hypothesis is that glycerol-induced hyperhydration (GIH) can accomplish extravascular fluid expansion because of the high solubility of glycerol in lipid and aqueous media. A hypertonic solution of glycerol is rapidly absorbed from the gastrointestinal tract, results in mild increases in plasma osmolality and is distributed to 65 percent of the body mass. A large volume of water ingested within minutes after glycerol intake results in increased total body water because of the osmotic action and distribution of glycerol. The resulting expanded extravascular fluid space can act as a reservoir to maintain plasma volume during exposure to dehydrating environments. The fluid shifts associated with exposure to microgravity result in increased urine production and is another example of an environment which induces hypohydration. Our goal is to demonstrate that GIH will facilitate maintenance of euhydration and cardiovascular performance during space flight and upon return to a 1 g environment.

  15. 15-Deoxy-Δ12,14-prostaglandin J2-Glycerol Ester, a Putative Metabolite of 2-Arachidonyl Glycerol, Activates Peroxisome Proliferator Activated Receptor γ

    PubMed Central

    Raman, Priyadarshini; Kaplan, Barbara L. F.; Thompson, Jerry T.; Vanden Heuvel, John P.

    2011-01-01

    2-Arachidonyl glycerol (2-AG) is an endogenous arachidonic acid derivative capable of suppressing interleukin (IL)-2 production by activated T cells. 2-AG-mediated IL-2 suppression is dependent on cyclooxygenase-2 (COX-2) metabolism and peroxisome proliferator activated receptor γ (PPARγ) activation. The objective of the present studies was to examine whether 15-deoxy-Δ12,14-PGJ2-glycerol ester (15d-PGJ2-G), a putative metabolite of 2-AG, can mimic the actions of 2-AG on IL-2 regulation through PPARγ activation. 15d-PGJ2-G bound PPARγ-ligand binding domain in a PPARγ competitive binding assay. 15d-PGJ2-G treatment activated PPARγ in a reporter assay, and PPARγ activation was attenuated when a PPARγ antagonist, 2-chloro-5-nitro-N-4-pyridinylbenzamide (T0070907), was present. 15d-PGJ2-G treatment suppressed IL-2 production by activated Jurkat cells, which was partially attenuated when pretreated with T0070907. Moreover, IL-2 suppression was pronounced when 15d-PGJ2-G was present 30 min before or after T-cell activation. Concordant with IL-2 suppression, 15d-PGJ2-G treatment decreased nuclear factor of activated T cells (NFAT) transcriptional activity in transiently transfected Jurkat cells. It is noteworthy that T0070907 alone markedly increased NFAT reporter activity, suggesting the existence of endogenous PPARγ activation and modulation of NFAT. Because COX-2 metabolism of 2-AG is important for IL-2 suppression, the effect of 2-AG on COX-2 and PPARγ mRNA expression was investigated. 2-AG treatment decreased the up-regulation of COX-2 mRNA after T-cell activation, which suggests negative feedback limiting COX-2-mediated metabolism of 2-AG. PPARγ mRNA expression was increased upon activation, and 2-AG treatment produced a modest decrease in PPARγ mRNA expression. Collectively, our findings suggest that 15d-PGJ2-G activates PPARγ to decrease NFAT transcriptional activity and IL-2 expression in activated T cells. PMID:21511917

  16. Anandamide and 2-AG Are Endogenously Present within the Laterodorsal Tegmental Nucleus: Functional Implications for a role of eCBs in arousal.

    PubMed

    Soni, Neeraj; Prabhala, Bala Krishna; Mehta, Ved; Mirza, Osman; Kohlmeier, Kristi Anne

    2017-04-09

    Previously, we presented electrophysiological evidence for presence in mice brain slices of functional cannabinoid type I receptors (CB1Rs) within the laterodorsal tegmentum (LDT), a brain stem nucleus critical in control of arousal and rapid eye movement (REM) sleep. Further, using pharmacological agents, we provided data suggestive of the endogenous presence of cannabinoids (CBs) acting at LDT CB1Rs. However, in those studies, we were unable to identify the type(s) of CB ligands endogenously present in the LDT, and this information has not been provided elsewhere. Accordingly, we used the highly-sensitive liquid chromatography/mass spectrometry (LC-MS) method to determine whether N-arachidonoylethanolamide (Anandamide or AEA) and 2-arachidonyl glycerol (2-AG), which are both endogenous CB ligands acting at CB1Rs, are present in the LDT. Mice brain tissue samples of the LDT were assayed using ion trap LC-MS in selected ion monitoring mode. Chromatographic analysis and product-ion MS scans identified presence of the CBs, AEA and 2-AG, from LDT mouse tissue. Data using the LC-MS method show that AEA and 2-AG are endogenously present within the LDT and when coupled with our electrophysiological findings, lead to the suggestion that AEA and 2-AG act at electropharmacologically-demonstrated CB1Rs in this nucleus. Accordingly, AEA and 2-AG likely play a role in processes governed by the LDT, including control of states of cortical gamma band activity seen in alert, aroused states, as well as cortical and motor activity characteristic of REM sleep.

  17. Characterization of crude glycerol from biodiesel plants.

    PubMed

    Hu, Shengjun; Luo, Xiaolan; Wan, Caixia; Li, Yebo

    2012-06-13

    Characterization of crude glycerol is very important to its value-added conversion. In this study, the physical and chemical properties of five biodiesel-derived crude glycerol samples were determined. Three methods, including iodometric-periodic acid method, high performance liquid chromatography (HPLC), and gas chromatography (GC), were shown to be suitable for the determination of glycerol content in crude glycerol. The compositional analysis of crude glycerol was successfully achieved by crude glycerol fractionation and characterization of the obtained fractions (aqueous and organic) using titrimetric, HPLC, and GC analyses. The aqueous fraction consisted mainly of glycerol, methanol, and water, while the organic fraction contained fatty acid methyl esters (FAMEs), free fatty acids (FFAs), and glycerides. Despite the wide variations in the proportion of their components, all raw crude glycerol samples were shown to contain glycerol, soap, methanol, FAMEs, water, glycerides, FFAs, and ash.

  18. Glycerol production of various strains of saccharomyces

    SciTech Connect

    Radler, F.; Schuetz, H.

    1982-01-01

    The quantity of glycerol as principal by-product of the alcoholic fermentation depends to a large extent on the yeast strain. Different strains of Saccharomyces cerevisiae were found to form amounts of glycerol varying between 4.2 to 10.4 g/L. The formation of glycerol is regarded as a result of the competition between alcohol dehydrogenase and glycerol-3-phosphate dehydrogenase that compete for the reduced coenzyme NADH/sub 2/. High and low glycerol forming yeast strains showed large differences in the activity of glycerol-3-phosphate dehydrogenase and only small variation in the activity of alcohol dehydrogenase. The total amount of glycerol formed was also influenced by amino acids. In thiamine deficient media a decrease in glycerol formation was observed. Experiments indicate a correlation between the formation of acetaldehyde and glycerol and the production of cell mass that may be of practical interest. (Refs. 12).

  19. Glycerol inhibition of ruminal lipolysis in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of...

  20. Production of glycerol by Hansenula anomala

    SciTech Connect

    Parekh, S.R.; Pandey, N.K.

    1985-07-01

    Production of glycerol by Hansenula anomala in molasses-corn steep liquor based media was studied. The accumulation and yield of glycerol was dependent on the medium composition and aeration rate; pH control did not affect the yield. Intermittent addition of sugar during fermentation resulted in significant increase in production of glycerol. 13 references.

  1. Nano-TiO2@Ag/PVC film with enhanced antibacterial activities and photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Liu, Fajia; Liu, Hu; Li, Xiaoyun; Zhao, Huanyu; Zhu, Danping; Zheng, Yingying; Li, Chaorong

    2012-03-01

    The antibacterial and photocatalytic PVC film was prepared by doping heteronanostructure of TiO2 nanowire@Ag nanoparticles. TiO2 nanowire with 50-60 nm in diameter and 0.1 mm in length was prepared by a hydrothermal method, and Ag nanopartical about 5-10 nm in diameter was grafted on the surface of TiO2 nanowire evenly in the solution. The antimicrobial ability and the photocatalytic properties of the nano-TiO2@Ag/PVC film were systematically investigated by changing the influence factors such as the content of nano-TiO2@Ag, pH value and the cultivation condition. It confirmed that the nano-TiO2@Ag nanostructure could increase the antibacterial efficiency of the PVC film. Further, nano-TiO2@Ag/PVC film also showed enhanced photocatalytic activity to decompose Rhodmine B (RhB).

  2. Mathematical modeling of glycerol biotransformation

    NASA Astrophysics Data System (ADS)

    Popova-Krumova, Petya; Yankova, Sofia; Ilieva, Biliana

    2013-12-01

    A method for mathematical modeling of glycerol biotransformation by Klebsiella oxytoca is presented. Glycerol is a renewable resource for it is formed as a by-product during biodiesel production. Because of its large volume production, it seems to be a good idea to develop a technology that converts this waste into products of high value (1, 3-Propanediol; 2, 3-Butanediol). The kinetic model of this process consists of many equations and parameters. The minimization of the least square function will be used for model parameters identification. In cases of parameters identification in multiparameter models the minimization of the least square function is very difficult because it is multiextremal. This is the main problem in the multiextremal function minimization which will be solved on the base a hierarchical approach, using a polynomial approximation of the experimental data.

  3. Glycerol-3-phosphatase of Corynebacterium glutamicum.

    PubMed

    Lindner, Steffen N; Meiswinkel, Tobias M; Panhorst, Maren; Youn, Jung-Won; Wiefel, Lars; Wendisch, Volker F

    2012-06-15

    Formation of glycerol as by-product of amino acid production by Corynebacterium glutamicum has been observed under certain conditions, but the enzyme(s) involved in its synthesis from glycerol-3-phosphate were not known. It was shown here that cg1700 encodes an enzyme active as a glycerol-3-phosphatase (GPP) hydrolyzing glycerol-3-phosphate to inorganic phosphate and glycerol. GPP was found to be active as a homodimer. The enzyme preferred conditions of neutral pH and requires Mg²⁺ or Mn²⁺ for its activity. GPP dephosphorylated both L- and D-glycerol-3-phosphate with a preference for the D-enantiomer. The maximal activity of GPP was estimated to be 31.1 and 1.7 U mg⁻¹ with K(M) values of 3.8 and 2.9 mM for DL- and L-glycerol-3-phosphate, respectively. For physiological analysis a gpp deletion mutant was constructed and shown to lack the ability to produce detectable glycerol concentrations. Vice versa, gpp overexpression increased glycerol accumulation during growth in fructose minimal medium. It has been demonstrated previously that intracellular accumulation of glycerol-3-phosphate is growth inhibitory as shown for a recombinant C. glutamicum strain overproducing glycerokinase and glycerol facilitator genes from E. coli in media containing glycerol. In this strain, overexpression of gpp restored growth in the presence of glycerol as intracellular glycerol-3-phosphate concentrations were reduced to wild-type levels. In C. glutamicum wild type, GPP was shown to be involved in utilization of DL-glycerol-3-phosphate as source of phosphorus, since growth with DL-glycerol-3-phosphate as sole phosphorus source was reduced in the gpp deletion strain whereas it was accelerated upon gpp overexpression. As GPP homologues were found to be encoded in the genomes of many other bacteria, the gpp homologues of Escherichia coli (b2293) and Bacillus subtilis (BSU09240, BSU34970) as well as gpp1 from the plant Arabidosis thaliana were overexpressed in E. coli MG1655 and

  4. Enhancing biological phosphorus removal with glycerol.

    PubMed

    Yuan, Q; Sparling, R; Lagasse, P; Lee, Y M; Taniguchi, D; Oleszkiewicz, J A

    2010-01-01

    An enhanced biological phosphorus removal process (EBPR) was successfully operated in presence of acetate. When glycerol was substituted for acetate in the feed the EBPR process failed. Subsequently waste activated sludge (WAS) from the reactor was removed to an off-line fermenter. The same amount of glycerol was added to the WAS fermenter which led to significant volatile fatty acids (VFA) production. By supplying the system with the VFA-enriched supernatant of the fermentate, biological phosphorus removal was enhanced. It was concluded that, if glycerol was to be used as an external carbon source in EBPR, the effective approach was to ferment glycerol with waste activated sludge.

  5. Harnessing the Endocannabinoid 2-Arachidonoylglycerol to Lower Intraocular Pressure in a Murine Model

    PubMed Central

    Miller, Sally; Leishman, Emma; Hu, Sherry Shujung; Elghouche, Alhasan; Daily, Laura; Murataeva, Natalia; Bradshaw, Heather; Straiker, Alex

    2016-01-01

    Purpose Cannabinoids, such as Δ9-THC, act through an endogenous signaling system in the vertebrate eye that reduces IOP via CB1 receptors. Endogenous cannabinoid (eCB) ligand, 2-arachidonoyl glycerol (2-AG), likewise activates CB1 and is metabolized by monoacylglycerol lipase (MAGL). We investigated ocular 2-AG and its regulation by MAGL and the therapeutic potential of harnessing eCBs to lower IOP. Methods We tested the effect of topical application of 2-AG and MAGL blockers in normotensive mice and examined changes in eCB-related lipid species in the eyes and spinal cord of MAGL knockout (MAGL−/−) mice using high performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). We also examined the protein distribution of MAGL in the mouse anterior chamber. Results 2-Arachidonoyl glycerol reliably lowered IOP in a CB1- and concentration-dependent manner. Monoacylglycerol lipase is expressed prominently in nonpigmented ciliary epithelium. The MAGL blocker KML29, but not JZL184, lowered IOP. The ability of CB1 to lower IOP is not desensitized in MAGL−/− mice. Ocular monoacylglycerols, including 2-AG, are elevated in MAGL−/− mice but, in contrast to the spinal cord, arachidonic acid and prostaglandins are not changed. Conclusions Our data confirm a central role for MAGL in metabolism of ocular 2-AG and related lipid species, and that endogenous 2-AG can be harnessed to reduce IOP. The MAGL blocker KML29 has promise as a therapeutic agent, while JZL184 may have difficulty crossing the cornea. These data, combined with the relative specificity of MAGL for ocular monoacylglycerols and the lack of desensitization in MAGL−/− mice, suggest that the development of an optimized MAGL blocker offers therapeutic potential for treatment of elevated IOP. PMID:27333182

  6. Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

    NASA Astrophysics Data System (ADS)

    Blyth, Alison J.; Schouten, Stefan

    2013-05-01

    Palaeotemperature proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) lipids have been established for marine and lacustrine environments, but there has been relatively little study of their application in speleothems. In this study we analyse the GDGT content of 33 speleothem samples from 16 different sites around the globe, and test whether proxies based on isoprenoid tetraethers (TEX86) or branched tetraethers (MBT/CBT) are correlated with measured surface and cave mean annual air temperature (MAT). The results show that the TEX86 has a strong relationship with measured temperature (r2 = 0.78, standard error of the estimate 2.3 °C, when calibrated with surface MAT). Furthermore, the MBT/CBT also showed a significant relationship with temperature (r2 = 0.73, standard error of the estimate 2.7 °C, when calibrated with surface MAT). Some issues remain requiring future work, in particular the development of a larger calibration sample set with measured cave temperature data, and the investigation of controls other than temperature on GDGT distribution, but overall the results indicate that GDGT based proxies derived from speleothems may be highly viable new methods for reconstructing continental palaeotemperatures.

  7. Orbital Orderings and Optical Conductivity in Cs2AgF4

    NASA Astrophysics Data System (ADS)

    Zhang, Min-Ping; Qian, Yu-Min; Wang, Guang-Tao

    The Jahn-Teller (JT) distortion induced orbital order and optical-conductivity in Cs2AgF4 are investigated by first-principle calculations. Cs2AgF4 contains 4d9 Ag2+, similar to 3d9 Cu2+ of La2CuO4. Although Cs2AgF4 is an isoelectronic analogue of La2CuO4, their magnetisms are radically different: La2CuO4 is antiferromagnetism (AFM), while Cs2AgF4 is proposed to be ferromagnetism (FM) based on recent neutron scattering data. The great difference can be understood from the JT distortions in the AgF6 octahedron, which favors the formation of staggered orbital order of dz2-x2 and dz2-y2. Such orbital order favors FM state, according to Goodenough-Kanamori Rules. We find when the JT distortion is larger than 0.03, the ground state of Cs2AgF4 is AFM. This antiferromagnetism might induce superconductivity, just as La2CuO4. In order to confirm such orbital order of Ag, we present the calculated optical-conductivity, which could be examined by experiment.

  8. Esters of oligo-(glycerol carbonate-glycerol): New biobased oligomeric surfactants.

    PubMed

    Holmiere, Sébastien; Valentin, Romain; Maréchal, Philippe; Mouloungui, Zéphirin

    2017-02-01

    Glycerol carbonate is one of the most potentially multifunction glycerol-derived compounds. Glycerol is an important by-product of the oleochemical industry. The oligomerization of glycerol carbonate, assisted by the glycerol, results in the production of polyhydroxylated oligomers rich in linear carbonate groups. The polar moieties of these oligomers (Mw<1000Da) were supplied by glycerol and glycerol carbonate rather than ethylene oxide as in most commercial surfactants. The insertion of linear carbonate groups into the glycerol-based skeleton rendered the oligomers amphiphilic, resulting in a decrease in air/water surface tension to 57mN/m. We improved the physical and chemical properties of the oligomers, by altering the type of acylation reaction and the nature of the acyl donor. The polar head is constituted of homo-oligomers and hetero-oligomers. Homo-oligomers are oligoglycerol and/or oligocarbonate, hetero-oligomers are oligo(glycerol-glycerol carbonate). Coprah oligoesters had the best surfactant properties (CMC<1mg/mL, πcmc<30mN/m), outperforming molecules of fossil origin, such as ethylene glycol monododecyl ether, glycol ethers and fatty acid esters of sorbitan polyethoxylates. The self-assembling properties of oligocarbonate esters were highlighted by their ability to stabilize inverse and multiple emulsions. The oligo-(glycerol carbonate-glycerol ether) with relatively low molecular weights showed properties of relatively high-molecular weight molecules, and constitute a viable "green" alternative to ethoxylated surfactants.

  9. Enhanced photocatalytic activity of Ag-TiO2/Ag heterogeneous films

    NASA Astrophysics Data System (ADS)

    Liang, Ying; Wang, ShaoHua; Guo, PengFeng

    2015-11-01

    Ag-deposited TiO2 and Ag (Ag-TiO2/Ag) films coated on glass substrates were prepared using a simple sol-gel and dip-coating method. The Ag chemical state was investigated through X-ray diffractometry and X-ray photoelectron spectroscopy. Results showed that the Ag mainly exists in metallic state in the Ag-TiO2 film. Ag-TiO2/Ag exhibits higher photocatalytic activity than individual Ag-TiO2 and TiO2/Ag films. This enhanced photocatalytic activity was attributed to high surface plasmon resonance effects and separation rates of photoinduced electron-hole pairs of Ag nanoparticles. Results were verified by photoluminescence and UV-Vis spectroscopy.

  10. Toward glycerol biorefinery: metabolic engineering for the production of biofuels and chemicals from glycerol.

    PubMed

    Chen, Zhen; Liu, Dehua

    2016-01-01

    As an inevitable by-product of the biofuel industry, glycerol is becoming an attractive feedstock for biorefinery due to its abundance, low price and high degree of reduction. Converting crude glycerol into value-added products is important to increase the economic viability of the biofuel industry. Metabolic engineering of industrial strains to improve its performance and to enlarge the product spectrum of glycerol biotransformation process is highly important toward glycerol biorefinery. This review focuses on recent metabolic engineering efforts as well as challenges involved in the utilization of glycerol as feedstock for the production of fuels and chemicals, especially for the production of diols, organic acids and biofuels.

  11. Glycerol citrate polyesters produced through microwave heating

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of various heating methods without catalysis to prepare copolyesters from citric acid:glycerol blends were studied. In the presence of short term microwave treatments, i.e., 60 sec at 1200 W, blends of glycerol and citric acid invariably formed solid amorphous copolyesters. Fourier tra...

  12. Thermal and physical characterization of glycerol polyesters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol polyesters were prepared by the condensation of glycerol and adipic acid, azelaic acid, sebacic acid, or suberic acids. After 48 hours at 125 deg C the polymers were clear and flexible. Samples of the reaction mixtures were analyzed by modulated differential scanning calorimetry to identi...

  13. From ether to acid: A plausible degradation pathway of glycerol dialkyl glycerol tetraethers

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Lei; Birgel, Daniel; Elling, Felix J.; Sutton, Paul A.; Lipp, Julius S.; Zhu, Rong; Zhang, Chuanlun; Könneke, Martin; Peckmann, Jörn; Rowland, Steven J.; Summons, Roger E.; Hinrichs, Kai-Uwe

    2016-06-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous microbial lipids with extensive demonstrated and potential roles as paleoenvironmental proxies. Despite the great attention they receive, comparatively little is known regarding their diagenetic fate. Putative degradation products of GDGTs, identified as hydroxyl and carboxyl derivatives, were detected in lipid extracts of marine sediment, seep carbonate, hot spring sediment and cells of the marine thaumarchaeon Nitrosopumilus maritimus. The distribution of GDGT degradation products in environmental samples suggests that both biotic and abiotic processes act as sinks for GDGTs. More than a hundred newly recognized degradation products afford a view of the stepwise degradation of GDGT via (1) ether bond hydrolysis yielding hydroxyl isoprenoids, namely, GDGTol (glycerol dialkyl glycerol triether alcohol), GMGD (glycerol monobiphytanyl glycerol diether), GDD (glycerol dibiphytanol diether), GMM (glycerol monobiphytanol monoether) and bpdiol (biphytanic diol); (2) oxidation of isoprenoidal alcohols into corresponding carboxyl derivatives and (3) chain shortening to yield C39 and smaller isoprenoids. This plausible GDGT degradation pathway from glycerol ethers to isoprenoidal fatty acids provides the link to commonly detected head-to-head linked long chain isoprenoidal hydrocarbons in petroleum and sediment samples. The problematic C80 to C82 tetraacids that cause naphthenate deposits in some oil production facilities can be generated from H-shaped glycerol monoalkyl glycerol tetraethers (GMGTs) following the same process, as indicated by the distribution of related derivatives in hydrothermally influenced sediments.

  14. Antibacterial effect of visible light reactive TiO2/Ag nanocomposite thin film on the orthodontic appliances.

    PubMed

    Yun, Kwidug; Oh, Gyejeong; Vang, Mongsook; Yang, Hongso; Lim, Hyunpil; Koh, Jeongtae; Jeong, Woonjo; Yoon, Dongjoo; Lee, Kyungku; Lee, Kwangmin; Park, Sangwon

    2011-08-01

    This study evaluated the antibacterial effect of a visible light reactive TiO2/Ag nanocomposite thin film on dental orthodontic wire (STS 304 wire). The growth of S. mutans and A. actinomycetemcomitans was suppressed on the specimens coated with TiO2/Ag compared to the uncoated specimens. The antibacterial effect of the TiO2/Ag nanocomposite thin film was improved under visible light irradiation.

  15. Biosynthesis of glycerol carbonate from glycerol by lipase in dimethyl carbonate as the solvent.

    PubMed

    Lee, Kyung Hwa; Park, Chang-Ho; Lee, Eun Yeol

    2010-11-01

    Glycerol carbonate was synthesized from renewable glycerol and dimethyl carbonate using lipase in solvent-free reaction system in which excess dimethyl carbonate played as the reaction medium. A variety of lipases have been tested for their abilities to catalyze transesterification reaction, and Candida antartica lipase B and Novozyme 435 exhibited higher catalytic activities. The silica-coated glycerol with a 1:1 ratio was supplied to prevent two-phase formation between hydrophobic dimethyl carbonate and hydrophilic glycerol. Glycerol carbonate was successfully synthesized with more than 90% conversion from dimethyl carbonate and glycerol with a molar ratio of 10 using Novozyme 435-catalyzed transesterification at 70 °C. The Novozyme 435 [5% (w/w) and 20% (w/w)] and silica gel were more than four times recycled with good stability in a repeated batch operation for the solvent-free synthesis of glycerol carbonate.

  16. Long-Chain Glycerol Diether and Polyol Dialkyl Glycerol Triether Lipids of Sulfolobus acidocaldarius

    PubMed Central

    Langworthy, Thomas A.; Mayberry, William R.; Smith, Paul F.

    1974-01-01

    Cells of Sulfolobus acidocaldarius contain about 2.5% total lipid on a dry-weight basis. Total lipid was found to contain 10.5% neutral lipid, 67.6% glycolipid, and 21.7% polar lipid. The lipids contained C40H80 isopranol glycerol diethers. Almost no fatty acids were present. The glycolipids were composed of about equal amounts of the glycerol diether analogue of glucosyl galactosyl diglyceride and a glucosyl polyol glycerol diether. The latter compound contained an unidentified polyol attached by an ether bond to the glycerol diether. The polar lipids contained a small amount of sulfolipid, which appeared to be the monosulfate derivative of glucosyl polyol glycerol diether. About 40% of the lipid phosphorus was found in the diether analogue of phosphatidyl inositol. The remaining lipid phosphorus was accounted for by approximately equal amounts of two inositol monophosphate-containing phosphoglycolipids, inositolphosphoryl glucosyl galactosyl glycerol diether and inositolphosphoryl glucosyl polyol glycerol diether. Images PMID:4407015

  17. Long-chain glycerol diether and polyol dialkyl glycerol triether lipids of Sulfolobus acidocaldarius.

    PubMed

    Langworthy, T A; Mayberry, W R; Smith, P F

    1974-07-01

    Cells of Sulfolobus acidocaldarius contain about 2.5% total lipid on a dry-weight basis. Total lipid was found to contain 10.5% neutral lipid, 67.6% glycolipid, and 21.7% polar lipid. The lipids contained C(40)H(80) isopranol glycerol diethers. Almost no fatty acids were present. The glycolipids were composed of about equal amounts of the glycerol diether analogue of glucosyl galactosyl diglyceride and a glucosyl polyol glycerol diether. The latter compound contained an unidentified polyol attached by an ether bond to the glycerol diether. The polar lipids contained a small amount of sulfolipid, which appeared to be the monosulfate derivative of glucosyl polyol glycerol diether. About 40% of the lipid phosphorus was found in the diether analogue of phosphatidyl inositol. The remaining lipid phosphorus was accounted for by approximately equal amounts of two inositol monophosphate-containing phosphoglycolipids, inositolphosphoryl glucosyl galactosyl glycerol diether and inositolphosphoryl glucosyl polyol glycerol diether.

  18. Microbial recycling of glycerol to biodiesel.

    PubMed

    Yang, Liu; Zhu, Zhi; Wang, Weihua; Lu, Xuefeng

    2013-12-01

    The sustainable supply of lipids is the bottleneck for current biodiesel production. Here microbial recycling of glycerol, byproduct of biodiesel production to biodiesel in engineered Escherichia coli strains was reported. The KC3 strain with capability of producing fatty acid ethyl esters (FAEEs) from glucose was used as a starting strain to optimize fermentation conditions when using glycerol as sole carbon source. The YL15 strain overexpressing double copies of atfA gene displayed 1.7-fold increase of FAEE productivity compared to the KC3 strain. The titer of FAEE in YL15 strain reached to 813 mg L(-1) in minimum medium using glycerol as sole carbon source under optimized fermentation conditions. The titer of glycerol-based FAEE production can be significantly increased by both genetic modifications and fermentation optimization. Microbial recycling of glycerol to biodiesel expands carbon sources for biodiesel production.

  19. Glycerol esters as fuel economy additives

    SciTech Connect

    Brewster, P.W.; Smith, C.R.; Gowland, F.W.

    1987-07-28

    A lubricating oil composition formulated is described for use as a crankcase lubricating oil composition for gasoline or diesel engines consisting essentially of a major amount of a mineral oil of a lubricating viscosity which has incorporated about 0.20 weight percent of a glycerol partial ester. The partial ester is a mixture of glycerol monooleate and glycerol dioleate. The mixture has a weight ratio of 3 parts of glycerol monooleate to 2 parts of glycerol dioleate the ester providing a fuel economy improvement of about 1 to 3 percent when the lubricating oil composition is employed in the crankcase of the engine. An ashless dispersant, a metal detergent additive, a zinc dihdyrocarbyl dithiophosphate anti-wear additive and an antioxidant. The dispersant, detergent, anti-wear additive and antioxidant are present in conventional amounts to provide their normal attendant functions.

  20. Exogenous delta⁹-tetrahydrocannabinol influences circulating endogenous cannabinoids in humans.

    PubMed

    Walter, Carmen; Ferreirós, Nerea; Bishay, Philipp; Geisslinger, Gerd; Tegeder, Irmgard; Lötsch, Jörn

    2013-10-01

    Delta⁹-tetrahydrocannabinol (THC) competes with the endogenous cannabinoids arachidonoyl ethanolamide (anandamide) and 2-arachidonoyl glycerol (2-AG) at cannabinoid receptors. This may cause adaptive changes in the endocannabinoid signaling cascade with possible consequences for the biological functions of the endocannabinoid system. We show that administration of a single oral dose of 20 mg THC to 30 healthy volunteers resulted in higher circulating concentrations of anandamide, 2-AG, palmitoyl ethanolamide, and oleoylethanolamide at 2 and 3 hours after administration as compared with placebo. At 2 hours after THC administration, changes in oleoylethanolamide plasma concentrations from baseline were linearly related to the THC plasma concentrations. In rats, treatment with the CB₁/CB₂ agonist WIN 55,212 also increased plasma endocannabinoid concentrations. However, this was associated with a decrease of ethanolamide endocannabinoids in specific brain regions including spinal cord, cortex, and hypothalamus; whereas 2-arachidonoyl glycerol increased in the cortex. Thus, administration of THC to human volunteers influenced the concentrations of circulating endocannabinoids, which was mimicked by WIN-55,212 in rats, suggesting that exogenous cannabinoids may lead to changes in the endocannabinoid system that can be detected in plasma.

  1. Ecotoxicology of Glycerol Monolaurate nanocapsules.

    PubMed

    Lopes, Leonardo Q S; Santos, Cayane G; de Almeida Vaucher, Rodrigo; Raffin, Renata P; da Silva, Aleksandro S; Baretta, Dilmar; Maccari, Ana Paula; Giombelli, Laura Caroline D D; Volpato, Andreia; Arruda, Jessyka; de Ávila Scheeren, Cecília; Baldisserotto, Bernardo; Santos, Roberto C V

    2017-05-01

    Glycerol Monolaurate (GML) is a compound with known antimicrobial potential, however it is not much used due to its low solubility in water and high melting point. The nanoencapsulation of some drugs offers several advantages such as improved stability and solubility in water. The present study aimed to produce, characterize, and evaluate the ecotoxicity of GML nanocapsules. The nanocapsules were produced and presented a mean diameter of 210nm, polydispersity index of 0.044, and zeta potential of -23.4mV. The electron microscopy images showed the nanometric size and spherical shape. The assay in soil showed that GML has a high toxicity while the GML nanocapsules showed decreased toxic effects. Nanostructuration also protected the Rhamdia quelen against the toxic effects of GML. Concluding, the formulation shows positive results and is useful to predict the success of development besides not damaging the soil.

  2. Wavelength-switchable photocurrent in a hybrid TiO2-Ag nanocluster photoelectrode.

    PubMed

    Chen, Hongjun; Wang, Qiong; Lyu, Miaoqiang; Zhang, Zhi; Wang, Lianzhou

    2015-08-04

    A hybrid TiO2-Ag nanocluster (NC) photoelectrode demonstrates unique wavelength-switchable photocurrent. By simply tuning the light wavelength from ultraviolet (UV) to visible light, the photocurrent generated on a single electrode can be switched from anodic to cathodic current, in which the Ag NCs behave like a new type of visible light active photocatalyst.

  3. Two potential fish glycerol-3-phosphate phosphatases.

    PubMed

    Raymond, James A

    2015-06-01

    Winter-acclimated rainbow smelt (Osmerus mordax Mitchill) produce high levels of glycerol as an antifreeze. A common pathway to glycerol involves the enzyme glycerol-3-phosphate phosphatase (GPP), but no GPP has yet been identified in fish or any other animal. Here, two phosphatases assembled from existing EST libraries (from winter-acclimated smelt and cold-acclimated smelt hepatocytes) were found to resemble a glycerol-associated phosphatase from a glycerol-producing alga, Dunaliella salina, and a recently discovered GPP from a bacterium, Mycobacterium tuberculosis. Recombinant proteins were generated and were found to have GPP activity on the order of a few μMol Pi/mg enzyme/min. The two enzymes have acidic pH optima (~5.5) similar to that previously determined for GPP activity in liver tissue, with about 1/3 of their peak activities at neutral pH. The two enzymes appear to account for the GPP activity of smelt liver, but due to their reduced activities at neutral pH, their contributions to glycerol production in vivo remain unclear. Similar enzymes may be active in a glycerol-producing insect, Dendroctonus ponderosae.

  4. Glycerol in micellar confinement with tunable rigidity

    NASA Astrophysics Data System (ADS)

    Lannert, Michael; Müller, Allyn; Gouirand, Emmanuel; Talluto, Vincenzo; Rosenstihl, Markus; Walther, Thomas; Stühn, Bernd; Blochowicz, Thomas; Vogel, Michael

    2016-12-01

    We investigate the glassy dynamics of glycerol in the confinement of a microemulsion system, which is stable on cooling down to the glass transition of its components. By changing the composition, we vary the viscosity of the matrix, while keeping the confining geometry intact, as is demonstrated by small angle X-ray scattering. By means of 2H NMR, differential scanning calorimetry, and triplet solvation dynamics we, thus, probe the dynamics of glycerol in confinements of varying rigidity. 2H NMR results show that, at higher temperatures, the dynamics of confined glycerol is unchanged compared to bulk behavior, while the reorientation of glycerol molecules becomes significantly faster than in the bulk in the deeply supercooled regime. However, comparison of different 2H NMR findings with data from calorimetry and solvation dynamics reveals that this acceleration is not due to the changed structural relaxation of glycerol, but rather due to the rotational motion of essentially rigid glycerol droplets or of aggregates of such droplets in a more fluid matrix. Thus, independent of the matrix mobility, the glycerol dynamics remains unchanged except for the smallest droplets, where an increase of Tg and, thus, a slowdown of the structural relaxation is observed even in a fluid matrix.

  5. Ethanolysis of rapeseed oil - distribution of ethyl esters, glycerides and glycerol between ester and glycerol phases.

    PubMed

    Cernoch, Michal; Hájek, Martin; Skopal, Frantisek

    2010-04-01

    The distribution of ethyl esters, triglycerides, diglycerides, monoglycerides, and glycerol between the ester and glycerol phase was investigated after the ethanolysis of rapeseed oil at various reaction conditions. The determination of these substances in the ester and glycerol phases was carried out by the GC method. The amount of ethyl esters in the glycerol phase was unexpectedly high and therefore the possibility of the reduction of this amount was investigated. The distribution coefficients and the weight distributions of each investigated substance were calculated and compared mutually. The distribution coefficients between the ester and glycerol phase increase in this sequence: glycerol, monoglycerides, diglycerides, ethyl esters, and triglycerides. Soaps and monoglycerides in the reaction mixture cause a worse separation of ethyl esters from the reaction mixture. The existence of a non-separable reaction mixture was observed also, and its composition was determined.

  6. Synthesis of prebiotic glycerol in interstellar ices.

    PubMed

    Kaiser, Ralf I; Maity, Surajit; Jones, Brant M

    2015-01-02

    Contemporary mechanisms for the spontaneous formation of glycerol have not been able to explain its existence on early Earth. The exogenous origin and delivery of organic molecules to early Earth presents an alternative route to their terrestrial in situ formation since biorelevant molecules like amino acids, carboxylic acids, and alkylphosphonic acids have been recovered from carbonaceous chondrites. Reported herein is the first in situ identification of glycerol, the key building block of all cellular membranes, formed by exposure of methanol-based - interstellar model ices to ionizing radiation in the form of energetic electrons. These results provide compelling evidence that the radiation-induced formation of glycerol in low-temperature interstellar model ices is facile. Synthesized on interstellar grains and eventually incorporated into the "building material" of solar systems, biorelevant molecules such as glycerol could have been dispensed to habitable planets such as early Earth by comets and meteorites.

  7. Efficient green methanol synthesis from glycerol

    NASA Astrophysics Data System (ADS)

    Haider, Muhammad H.; Dummer, Nicholas F.; Knight, David W.; Jenkins, Robert L.; Howard, Mark; Moulijn, Jacob; Taylor, Stuart H.; Hutchings, Graham J.

    2015-12-01

    The production of biodiesel from the transesterification of plant-derived triglycerides with methanol has been commercialized extensively. Impure glycerol is obtained as a by-product at roughly one-tenth the mass of the biodiesel. Utilization of this crude glycerol is important in improving the viability of the overall process. Here we show that crude glycerol can be reacted with water over very simple basic or redox oxide catalysts to produce methanol in high yields, together with other useful chemicals, in a one-step low-pressure process. Our discovery opens up the possibility of recycling the crude glycerol produced during biodiesel manufacture. Furthermore, we show that molecules containing at least two hydroxyl groups can be converted into methanol, which demonstrates some aspects of the generality of this new chemistry.

  8. Insoluble and flexible silk films containing glycerol.

    PubMed

    Lu, Shenzhou; Wang, Xiaoqin; Lu, Qiang; Zhang, Xiaohui; Kluge, Jonathan A; Uppal, Neha; Omenetto, Fiorenzo; Kaplan, David L

    2010-01-11

    We directly prepared insoluble silk films by blending with glycerol and avoiding the use of organic solvents. The ability to blend a plasticizer like glycerol with a hydrophobic protein like silk and achieve stable material systems above a critical threshold of glycerol is an important new finding with importance for green chemistry approaches to new and more flexible silk-based biomaterials. The aqueous solubility, biocompatibility, and well-documented use of glycerol as a plasticizer with other biopolymers prompted its inclusion in silk fibroin solutions to assess impact on silk film behavior. Processing was performed in water rather than organic solvents to enhance the potential biocompatibility of these biomaterials. The films exhibited modified morphologies that could be controlled on the basis of the blend composition and also exhibited altered mechanical properties, such as improved elongation at break, when compared with pure silk fibroin films. Mechanistically, glycerol appears to replace water in silk fibroin chain hydration, resulting in the initial stabilization of helical structures in the films, as opposed to random coil or beta-sheet structures. The use of glycerol in combination with silk fibroin in materials processing expands the functional features attainable with this fibrous protein, and in particular, in the formation of more flexible films with potential utility in a range of biomaterial and device applications.

  9. Structure and physical properties of RE{sub 2}AgGe{sub 3} (RE=Ce, Pr, Nd) compounds

    SciTech Connect

    Sarkar, Sumanta; Mumbaraddi, Dundappa; Halappa, Pramod; Kalsi, Deepti; Rayaprol, Sudhindra; Peter, Sebastian C.

    2015-09-15

    We have synthesized the compounds RE{sub 2}AgGe{sub 3} (RE =Ce, Pr, Nd) by arc melting. The crystal structure obtained from single crystal and powder X-ray diffraction suggests that these compounds crystallize in the α-ThSi{sub 2} structure type. The magnetic susceptibility data of Ce{sub 2}AgGe{sub 3} follows Curie–Weiss (CW) law above 25 K without any magnetic ordering down to 2 K. The effective magnetic moment (μ{sub eff}) was calculated as 2.53 μ{sub B}/Ce and negative Curie paramagnetic temperature (θ{sub p})=−2.4 K hint weak antiferromagnetic coupling among the adjacent spins. Pr{sub 2}AgGe{sub 3} shows a complex magnetic behavior wherein the magnetic susceptibility at field cooled and zero field cooled modes bifurcates at 11.5 K with the latter undergoing a cusp like maxima, probably due to weak ferromagnetic interaction. The θ{sub p} and μ{sub eff} obtained are 4 K and 4.33 μ{sub B}/Pr, respectively. Nd{sub 2}AgGe{sub 3} undergoes multiple magnetic transitions. Temperature dependent resistivity data reveals that three compounds are metallic in nature. - Graphical abstract: The compounds Ce{sub 2}AgGe{sub 3}, Pr{sub 2}AgGe{sub 3} and Nd{sub 2}AgGe{sub 3} have been synthesized by arc melting. X-ray diffraction suggests tetragonal α-ThSi{sub 2} type structure and diverse magnetic properties exhibited in the magnetic measurements. - Highlights: • Two new compounds Ce{sub 2}AgGe{sub 3}, Nd{sub 2}AgGe{sub 3} and known Pr{sub 2}AgGe{sub 3} synthesized by arc melting. • Crystal structure of the compounds derived from X-ray diffraction. • Ce{sub 2}AgGe{sub 3} and Pr{sub 2}AgGe{sub 3} exhibit antiferromagnetic ordering. • Nd{sub 2}AgGe{sub 3} shows multiple magnetic transition with ferrimagnetic like behavior.

  10. Synthesis and characterization of Fe3O4-SiO2-AgCl photocatalyst

    NASA Astrophysics Data System (ADS)

    Husni, H. N.; Mahmed, N.; Ngee, H. L.

    2016-07-01

    Magnetite-silica-silver chloride (Fe3O4-SiO2-AgCl) coreshell particles with AgCl crystallite size of 117 nm was prepared by a wet chemistry method at ambient temperature. The magnetite-core was synthesized by using iron (II) sulfate heptahydrate (FeSO4•7H2O) and iron (III) sulfate hydrate (Fe2(SO4)3) with ammonium hydroxide (NH4OH) as the precipitating agent. The silica-shell was synthesized by using a modified Stöber process. The silver ions (Ag+) was adsorbed onto the silica surface after Söber process, followed by the addition of Cl- and polyvinylpyrrolidone (PVP) for the formation of Fe3O4-SiO2-AgCl coreshell particles. The effectiveness of the synthesized photocatalyst was investigated by monitoring the degradation of the methylene blue (MB) under sunlight for five cycles. About 90 % of the MB solution can be degraded after 2 hours. The degradation of MB solution by the Fe3O4-SiO2-AgCl particles is highly efficient for first three cycles according to the MB concentration recorded by the UV-Visible spectroscopy (UV-Vis). Nevertheless, the synthesized particles could be a promising material for photocatalytic applications.

  11. Synthesis of natural cellulose-templated TiO2/Ag nanosponge composites and photocatalytic properties.

    PubMed

    Yu, Dong-Hui; Yu, Xiaodan; Wang, Changhua; Liu, Xian-Chun; Xing, Yan

    2012-05-01

    In this paper, TiO(2)/Ag sponge-like nanostructure composites have been prepared by the surface sol-gel method with the template of natural cellulose, which is relatively simple, low-cost, and environmentally friendly. The Ag nanoparticles are deposited on the TiO(2) nanosponges through UV irradiation photoreduction of silver nitrate solutions. The physicochemical properties of as-prepared composites are characterized by XRD, BET, SEM, TEM, XPS and UV-vis DRS techniques. The UV-light photocatalytic activities of the composites are evaluated through the photodegradation of two model organic molecules including RhB and salicylic acid. The experimental results show that the photocatalytic activities of TiO(2)/Ag nanosponge composites are superior to that of P25, pure TiO(2) nanoparticle aggregates synthesized by the hydrothermal method and pure TiO(2) nanosponge. The superior activities of TiO(2)/Ag nanosponge composite photocatalysts can be attributed to the unique nanosponge morphology, uniform dispersion of Ag nanoparticles, and strong interaction between Ag and TiO(2) nanosponges.

  12. Glycerol monooleate-blood interactions.

    PubMed

    Ericsson, Emma M; Faxälv, Lars; Weissenrieder, Anna; Askendal, Agneta; Lindahl, Tomas L; Tengvall, Pentti

    2009-01-01

    In the present study the initial blood compatibility of glycerol monooleate (GMO)-coated surfaces was evaluated after deposition to surfaces and in bulk. The model surface was silica onto which multiple layers of fibrinogen or human serum albumin (HSA) was immobilized. The protein-coated surfaces were subsequently dip-coated in GMO in ethanol and used for blood plasma and whole blood experiments. The characterization methods included null ellipsometry, scanning electron microscopy, imaging of coagulation, hemolysis test and whole blood coagulation time by free oscillation rheometry. The results showed a GMO film thickness of approximately 350 A (approximately 4 microg/cm(2)) upon dip-coating in ethanolic solution. A major part of the deposited layer detached in aqueous solutions, especially during shear conditions. The coagulation time on GMO was significantly prolonged compared to that on HSA coated silica. Whole blood tests showed that GMO is a very weak hemolytic agent. Deposited GMO detached easily from surfaces upon rinsing or shearing, although a stable layer with undefined phase structure and a thickness of 50-70 A remained on HSA and fibrinogen precoated surfaces. This indicates that GMO has stronger adhesive forces to its substrate compared to the cohesive forces acting within the bulk GMO. The ability of GMO to detach from itself and tentatively form micelles or lipid bilayers when subjected to flowing blood may be of use in extravascular applications. It is concluded that GMO results in weak blood activation, and the material may in spite of this be suitable in selected biomaterial applications, especially as a biosealant and in colloidal dispersions.

  13. Synthesis of Glycerol Carbonate by Transesterification of Glycerol with Urea Over Zn/Al Mixed Oxide.

    PubMed

    Ryu, Young Bok; Baek, Jae Ho; Kim, Yangdo; Lee, Man Sig

    2015-01-01

    Reactions of glycerol carbonate using glycerol and urea have been carried out previously using ZnSO4 and ZnO catalysts, and high yields have been reported using ZnSO4 as catalyst. However, this salt is soluble in glycerol, and recycling of catalyst is difficult after the reaction. In this study, we prepared a mixed metal oxide catalyst using Zn and Al, and this catalyst consisted of a mixture of ZnO and ZnAl2O4. We confirmed the conversion of glycerol and the yield of glycerol carbonate of the amount of Al. As a result, we obtained a yield of 82.3% and a conversion of 82.7%. In addition we obtained high yield in recycling of catalyst. The yield of the glycerol carbonate increases with an increase of acid and base site of catalysts and the highest catalytic activity was obtained when acid/base ratio was approx. 1. From this result, we may conclude that the acid and base site density and ratio of catalysts were very important parameters in the synthesis of glycerol carbonate from urea and glycerol.

  14. Glycerol elicits energy taxis of Escherichia coli and Salmonella typhimurium.

    PubMed

    Zhulin, I B; Rowsell, E H; Johnson, M S; Taylor, B L

    1997-05-01

    Escherichia coli and Salmonella typhimurium show positive chemotaxis to glycerol, a chemical previously reported to be a repellent for E. coli. The threshold of the attractant response in both species was 10(-6) M glycerol. Glycerol chemotaxis was energy dependent and coincident with an increase in membrane potential. Metabolism of glycerol was required for chemotaxis, and when lactate was present to maintain energy production in the absence of glycerol, the increases in membrane potential and chemotactic response upon addition of glycerol were abolished. Methylation of a chemotaxis receptor was not required for positive glycerol chemotaxis in E. coli or S. typhimurium but is involved in the negative chemotaxis of E. coli to high concentrations of glycerol. We propose that positive chemotaxis to glycerol in E. coli and S. typhimurium is an example of energy taxis mediated via a signal transduction pathway that responds to changes in the cellular energy level.

  15. Catalytic glycerol steam reforming for hydrogen production

    SciTech Connect

    Dan, Monica Mihet, Maria Lazar, Mihaela D.

    2015-12-23

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 2} adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 2}O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  16. Catalytic glycerol steam reforming for hydrogen production

    NASA Astrophysics Data System (ADS)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-12-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H2. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al2O3. The catalyst was prepared by wet impregnation method and characterized through different methods: N2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H2, CH4, CO, CO2. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H2O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%.

  17. Liquid dynamics in partially crystalline glycerol

    NASA Astrophysics Data System (ADS)

    Sanz, Alejandro; Niss, Kristine

    2017-01-01

    We present a dielectric study on the dynamics of supercooled glycerol during crystallization. We explore the transformation into a solid phase in real time by monitoring the temporal evolution of the amplitude of the dielectric signal. Neither the initial nucleation nor the crystal growth influences the liquid dynamics visibly. For one of the samples studied, a tiny fraction of glycerol remained in the disordered state after the end of the transition. We examined the nature of the α relaxation in this frustrated crystal and find that it is virtually identical to the bulk dynamics. In addition, we have found no evidence that supercooled glycerol transforms into a peculiar phase in which either a new solid amorphous state or nano-crystals dispersed in a liquid matrix are formed.

  18. Antibacterial and antifouling activities of chitosan/TiO2/Ag NPs nanocomposite films against packaged drinking water bacterial isolates.

    PubMed

    Natarajan, Saravanan; Bhuvaneshwari, M; Lakshmi, D Shanthana; Mrudula, P; Chandrasekaran, N; Mukherjee, Amitava

    2016-10-01

    TiO2 and Ag NPs are widely used as antibacterial agents against many bacterial pathogens. Chitosan (polymer) itself acts as a strong antibacterial agent. Hence, chitosan/TiO2/Ag NPs incorporated nanocomposite film was prepared against packed drinking water bacterial strains. A concentration-dependent increase in the reduction of cell viability was observed in all the isolates under UV-C and dark exposure conditions. The bacteria consortium showed greater resistance against antibacterial effects of chitosan/TiO2/Ag nanocomposite as compared to single isolates. Glycocalyx test and mass assessment conclude the effective antibacterial activity by inhibiting bacterial adhesion on the film surface. The release of LDH and generation of ROS act as the predominant antibacterial mechanism induced by TiO2/Ag NPs. Surface characterization of chitosan/TiO2/Ag nanocomposite was studied by FTIR and XRD analyses and SEM analysis after interaction with the bacteria.

  19. Bioconversion of glycerol to ethanol by a mutant Enterobacter aerogenes.

    PubMed

    Nwachukwu, Res; Shahbazi, A; Wang, L; Ibrahim, S; Worku, M; Schimmel, K

    2012-03-29

    The main objective of this research is to develop, by adaptive evolution, mutant strains of Enterobacter aerogenes ATCC 13048 that are capable of withstanding high glycerol concentration as well as resisting ethanol-inhibition. The mutant will be used for high ethanol fermentation from glycerol feedstock. Ethanol production from pure (P-) and recovered (R-) glycerol using the stock was evaluated. A six-tube-subculture-generations method was used for developing the mutant. This involved subculturing the organism six consecutive times in tubes containing the same glycerol and ethanol concentrations at the same culture conditions. Then, the glycerol and/or ethanol concentration was increased and the six subculture generations were repeated. A strain capable of growing in 200 g/L glycerol and 30 g/L ethanol was obtained. The ability of this mutant, vis-à-vis the original strain, in utilizing glycerol in a high glycerol containing medium, with the concomitant ethanol yield, was assessed. Tryptic soy broth without dextrose (TSB) was used as the fermentation medium. Fermentation products were analyzed using HPLC.In a 20 g/L glycerol TSB, E. aerogenes ATCC 13048 converted 18.5 g/L P-glycerol and 17.8 g/L R-glycerol into 12 and 12.8 g/L ethanol, respectively. In a 50 g/L P-glycerol TSB, it utilized only 15.6 g/L glycerol; but the new strain used up 39 g/L, yielding 20 g/L ethanol after 120 h, an equivalence of 1.02 mol ethanol/mol-glycerol. This is the highest ethanol yield reported from glycerol bioconversion. The result of this P-glycerol fermentation can be duplicated using the R-glycerol from biodiesel production.

  20. Replacing corn with glycerol in diets for transition dairy cows.

    PubMed

    Carvalho, E R; Schmelz-Roberts, N S; White, H M; Doane, P H; Donkin, S S

    2011-02-01

    Expansion of the biofuels industry has increased the availability of glycerol as an alternative feed for dairy cows. The objective of this study was to determine the effects of glycerol on feed intake, milk production, rumen volatile fatty acids, and metabolic parameters in transition dairy cows. Multiparous Holstein cows were fed diets containing either high-moisture corn (n=11) or glycerol (n=12) from -28 to +56 d relative to calving. Glycerol was included at 11.5 and 10.8% of the ration dry matter for the pre- and postpartum diets, respectively. Prepartum feed intake was not changed by glycerol feeding (14.9 vs. 14.6 kg/d, control vs. glycerol) nor did postpartum feed intake differ (19.8 vs. 20.7 kg/d, control vs. glycerol). Overall milk yield did not differ (35.8 vs. 37 kg/d, control vs. glycerol) and milk composition, milk urea nitrogen, somatic cells, and energy balance were not different with glycerol feeding. Blood glucose content was decreased in cows fed glycerol during the prepartum period (59.1 vs. 53.4 mg/dL), and β-hydroxybutyrate concentration was increased (0.58 vs. 0.82 mmol/L, control vs. glycerol). Concentrations of blood nonesterified fatty acids did not differ between the treatment groups, and no response to glycerol for blood metabolites during the postpartum period was observed. Total rumen volatile fatty acid concentrations (mmol/L) did not differ between treatments, but proportions of rumen propionate and butyrate were greater for cows fed glycerol (22.7 vs. 28.6% of propionate, control vs. glycerol; and 11.5 vs. 15.3% of butyrate, control vs. glycerol) at the expense of acetate (61.4 vs. 51.5%, control vs. glycerol). These data indicate that glycerol is a suitable replacement for corn grain in diets for transition dairy cows.

  1. Controlled preparation of porous TiO2-Ag nanostructures through supramolecular assembly for plasmon-enhanced photocatalysis.

    PubMed

    Fei, Jinbo; Li, Junbai

    2015-01-14

    By templating Ag(+)-induced supramolecular assembly at different temperatures, porous TiO2-Ag nanotubes and nanospheres are fabricated in a controlled manner due to the effect of Rayleigh instability. Compared with traditional TiO2 nanoparticles, TiO2-Ag nanostructures above show much more extensive visible light absorption and exhibit the noticeably plasmon-enhanced photocatalysis because of the existence of Ag nanoparticles.

  2. Biorefinery for Glycerol Rich Biodiesel Industry Waste.

    PubMed

    Kalia, Vipin Chandra; Prakash, Jyotsana; Koul, Shikha

    2016-06-01

    The biodiesel industry has the potential to meet the fuel requirements in the future. A few inherent lacunae of this bioprocess are the effluent, which is 10 % of the actual product, and the fact that it is 85 % glycerol along with a few impurities. Biological treatments of wastes have been known as a dependable and economical direction of overseeing them and bring some value added products as well. A novel eco-biotechnological strategy employs metabolically diverse bacteria, which ensures higher reproducibility and economics. In this article, we have opined, which organisms and what bioproducts should be the focus, while exploiting glycerol as feed.

  3. Dietary linoleic acid elevates endogenous 2-AG and anandamide and induces obesity.

    PubMed

    Alvheim, Anita R; Malde, Marian K; Osei-Hyiaman, Douglas; Lin, Yu Hong; Pawlosky, Robert J; Madsen, Lise; Kristiansen, Karsten; Frøyland, Livar; Hibbeln, Joseph R

    2012-10-01

    Suppressing hyperactive endocannabinoid tone is a critical target for reducing obesity. The backbone of both endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) is the ω-6 fatty acid arachidonic acid (AA). Here we posited that excessive dietary intake of linoleic acid (LA), the precursor of AA, would induce endocannabinoid hyperactivity and promote obesity. LA was isolated as an independent variable to reflect the dietary increase in LA from 1 percent of energy (en%) to 8 en% occurring in the United States during the 20th century. Mice were fed diets containing 1 en% LA, 8 en% LA, and 8 en% LA + 1 en% eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) in medium-fat diets (35 en% fat) and high-fat diets (60 en%) for 14 weeks from weaning. Increasing LA from 1 en% to 8 en% elevated AA-phospholipids (PL) in liver and erythrocytes, tripled 2-AG + 1-AG and AEA associated with increased food intake, feed efficiency, and adiposity in mice. Reducing AA-PL by adding 1 en% long-chain ω-3 fats to 8 en% LA diets resulted in metabolic patterns resembling 1 en% LA diets. Selectively reducing LA to 1 en% reversed the obesogenic properties of a 60 en% fat diet. These animal diets modeled 20th century increases of human LA consumption, changes that closely correlate with increasing prevalence rates of obesity. In summary, dietary LA increased tissue AA, and subsequently elevated 2-AG + 1-AG and AEA resulting in the development of diet-induced obesity. The adipogenic effect of LA can be prevented by consuming sufficient EPA and DHA to reduce the AA-PL pool and normalize endocannabinoid tone.

  4. Effects of intravenous infusion of glycerol on blood parameters and urinary glycerol concentrations.

    PubMed

    Okano, Masato; Nishitani, Yasunori; Dohi, Michiko; Kageyama, Shinji

    2016-05-01

    In sports, the oral intake and intravenous administration of glycerol as a potential masking agent have been prohibited. The effect of glycerol on blood parameters was investigated by comparing the intravenous administration of glycerol (20g/200mL) with that of an electrolyte (8g glucose/200mL) as a comparator (n=7, fixed-dose-rate i.v. infusion, 200mL in 1h). This study was also designed to evaluate whether the urinary concentrations reached the positivity threshold after the intravenous infusion of glycerol. Significant decreases of the haemoglobin (HGB, g/dL), haematocrit (HCT, %) and OFF-h Score (OFF-score) values were observed after the infusion of glycerol (P<0.05 at 1-6h). The differences in the HGB, HCT and OFF-score between pre- and post-administration were -0.49±0.23g/dL (2h), -1.54±0.73% (2h) and -3.89±3.66 (2h), respectively. Glycerol infusion significantly increased the plasma volume by 12.1% (1h), 6.3% (2h) and 5.7% (3h) compared with the initial values. The infusion of the comparator also increased the plasma volume by 9.6% (1h), 5.8% (2h) and 4.9% (3h) compared with the values before infusion. There were no significant differences in the change of the plasma volume between the intravenous infusions of glycerol and the glucose-based electrolyte (as the comparator) (P≥0.05). This finding might indicate that glycerol itself only exhibited limited effects on the expansion of plasma. After administration of glycerol, the urinary glycerol concentrations increased from 0.0013±0.0004mg/mL to 6.86±2.86mg/mL at 1h and 6.45±3.08mg/mL at 2h. The intravenous infusion of glycerol can most likely be detected using the current urine analysis; however, the dependence of the concentration of urinary glycerol on the urine volume should be considered.

  5. Glycerol production by fermentation: a fed-batch approach

    SciTech Connect

    Vijaikishore, P.; Karanth, N.G.

    1987-01-01

    In this investigation the bioconversion of glycerol from glucose was studied in a laboratory fermentor using an alkaline medium with a fed batch mode of carbon source addition yielding 30% glycerol concentration in the final broth. (Refs. 9).

  6. Evidence for direct binding of glycerol to photosystem I.

    PubMed

    Hussels, Martin; Brecht, Marc

    2011-08-04

    The interaction between glycerol and photosystem I (PSI) was investigated using low temperature single-molecule spectroscopy. PSI complexes were dissolved in three different solutions: in buffer solution, in 66% glycerol/buffer solution, and in 66% glycerol/buffer solution that was afterwards diluted by buffer; the final glycerol concentration was <1‰. Mean fluorescence spectra and intercomplex heterogeneity of PSI complexes in 66% glycerol/buffer solution and in the re-diluted solution show high similarity, but differ from complexes in buffer solution indicating that the glycerol concentration is not the determining factor modifying the spectral properties. However, the exposure of PSI to a high glycerol concentration during sample preparation affects PSI and the effect is maintained if glycerol is removed from the solution.

  7. Genetic construction of recombinant Pseudomonas chlororaphis for improved glycerol utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study is to improve by genetic engineering the glycerol metabolic capability of Pseudomonas chlororaphis which is capable of producing commercially valuable biodegradable poly(hydroxyalkanoate) (PHA) and biosurfactant rhamnolipids (RLs). In the study, glycerol uptake facilitat...

  8. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  9. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  10. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  11. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD....735 Glycerol ester of rosin. Glycerol ester of wood rosin, gum rosin, or tall oil rosin may be...

  12. 21 CFR 172.735 - Glycerol ester of rosin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Glycerol ester of rosin. 172.735 Section 172.735 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... CONSUMPTION Other Specific Usage Additives § 172.735 Glycerol ester of rosin. Glycerol ester of wood...

  13. Determining Atmospheric Pressure with a Eudiometer and Glycerol

    ERIC Educational Resources Information Center

    Brody, Jed; Rohald, Kate; Sutton, Atasha

    2010-01-01

    We consider a volume of air trapped over a glycerol column in a eudiometer. We demonstrate that there is an approximately linear relationship between the volume of trapped air and the height of the glycerol column. Simply by moving the eudiometer up and down, we cause the glycerol-column height and trapped-air volume to vary. The plot of volume…

  14. 1,2-Isopropylidene glycerol carbonate: preparation, characterization, and hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The utilization of excess glycerol supplies derived from the burgeoning biodiesel industry is of major importance to the oleochemical industry as the economic viability of the biodiesel and oleochemical industries are closely linked to glycerol prices. Carbonate compounds based on glycerol, such as...

  15. Digestable and Metabolizable Energy of Crude Glycerol in Growing Pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apparent DE and ME value of crude glycerol for growing pigs was determined in a series of 5 experiments using crude glycerol (86.95% glycerol) from a biodiesel production facility with soybean oil used as the initial feedstock (AG Processing Inc., Sergeant Bluff, IA). Dietary treatments were 0, ...

  16. Conversion of glycerol to hydrogen rich gas.

    PubMed

    Tran, Nguyen H; Kannangara, G S Kamali

    2013-12-21

    Presently there is a glut of glycerol as the by-product of biofuel production and it will grow as production increases. The conundrum is how we can consume this material and convert it into a more useful product. One potential route is to reform glycerol to hydrogen rich gas including synthesis gas (CO + H2) and hydrogen. However, there is recent literature on various reforming techniques which may have a bearing on the efficiency of such a process. Hence in this review reforming of glycerol at room temperature (normally photo-catalytic), catalysis at moderate and high temperature and a non-catalytic pyrolysis process are presented. The high temperature processes allow the generation of synthesis gas with the hydrogen to carbon monoxide ratios being suitable for synthesis of dimethyl ether, methanol and for the Fischer-Tropsch process using established catalysts. Efficient conversion of synthesis gas to hydrogen involves additional catalysts that assist the water gas shift reaction, or involves in situ capture of carbon dioxide and hydrogen. Reforming at reduced temperatures including photo-reforming offers the opportunity of producing synthesis gas or hydrogen using single catalysts. Together, these processes will assist in overcoming the worldwide glut of glycerol, increasing the competitiveness of the biofuel production and reducing our dependency on the fossil based, hydrogen rich gas.

  17. Rapid monitoring of glycerol in fermentation growth media: Facilitating crude glycerol bioprocess development.

    PubMed

    Abad, Sergi; Pérez, Xavier; Planas, Antoni; Turon, Xavier

    2014-04-01

    Recently, the need for crude glycerol valorisation from the biodiesel industry has generated many studies for practical and economic applications. Amongst them, fermentations based on glycerol media for the production of high value metabolites are prominent applications. This has generated a need to develop analytical techniques which allow fast and simple glycerol monitoring during fermentation. The methodology should be fast and inexpensive to be adopted in research, as well as in industrial applications. In this study three different methods were analysed and compared: two common methodologies based on liquid chromatography and enzymatic kits, and the new method based on a DotBlot assay coupled with image analysis. The new methodology is faster and cheaper than the other conventional methods, with comparable performance. Good linearity, precision and accuracy were achieved in the lower range (10 or 15 g/L to depletion), the most common range of glycerol concentrations to monitor fermentations in terms of growth kinetics.

  18. Effect of gamma irradiation on MnO2/Ag2O hydrogen getter

    NASA Astrophysics Data System (ADS)

    Chlique, Christophe; Lambertin, David; Galliez, Kévin; Labed, Véronique; Dannoux-Papin, Adeline; Jobic, Stéphane; Deniard, Philippe; Leoni, Elisa

    2015-03-01

    This study aims to show the stability of γ-MnO2/Ag2O hydrogen getter under gamma irradiation in order to be suitable for decreasing the hydrogen risk during the nuclear waste transportation. The chemical and the structural properties of the getter were barely unchanged for irradiated doses up to 4 MGy. The pair distribution function (PDF) analysis showed that the γ-MnO2, which can be describe as an intergrowth of the ramsdellite phase (R-MnO2) and the pyrolusite phase (β-MnO2), had the same intergrowth rate (around 60% for β-MnO2 and 40% for R-MnO2) after irradiation and the silver containing promoter was also unchanged. The getter remains therefore efficient for hydrogen trapping. Furthermore, γ-MnO2/Ag2O was tested in a closed environment in the presence of hydrogen released by organic technological waste radiolysis, such as polyvinyl chloride, ion exchange resins, polyethylene and silicone. Over 80% of the hydrogen, generated by organic radiolysis, was trapped under a 1.5 MGy gamma irradiation.

  19. Antioxidant behavior of 1-feruloyl-sn-glycerol and 1,3-diferuloyl-sn-glycerol in phospholipid liposomes 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1-Feruloyl-sn-glycerol (FG) and 1,3-diferuloyl-sn-glycerol (DFG) are two natural plant compounds that may be useful in cosmeceutical, food, and skin care applications because of excellent antioxidant properties. FG and DFG enzymatically synthesized through esterification of glycerol and soybean oil...

  20. An improved glycerol biosensor with an Au-FeS-NAD-glycerol-dehydrogenase anode.

    PubMed

    Mahadevan, Aishwarya; Fernando, Sandun

    2017-06-15

    An improved glycerol biosensor was developed via direct attachment of NAD(+)-glycerol dehydrogenase coenzyme-apoenzyme complex onto supporting gold electrodes, using novel inorganic iron (II) sulfide (FeS)-based single molecular wires. Sensing performance factors, i.e., sensitivity, a detection limit and response time of the FeS and conventional pyrroloquinoline quinone (PQQ)-based biosensor were evaluated by dynamic constant potential amperometry at 1.3V under non-buffered conditions. For glycerol concentrations ranging from 1 to 25mM, a 77% increase in sensitivity and a 53% decrease in detection limit were observed for the FeS-based biosensor when compared to the conventional PQQ-based counterpart. The electrochemical behavior of the FeS-based glycerol biosensor was analyzed at different concentrations of glycerol, accompanied by an investigation into the effects of applied potential and scan rate on the current response. Effects of enzyme stimulants ((NH4)2SO4 and MnCl2·4H2O) concentrations and buffers/pH (potassium phosphate buffer pH 6-8, Tris buffer pH 8-10) on the current responses generated by the FeS-based glycerol biosensor were also studied. The optimal detection conditions were 0.03M (NH4)2SO4 and 0.3µm MnCl2·4H2O in non-buffered aqueous electrolyte under stirring whereas under non-stirring, Tris buffer at pH 10 with 0.03M (NH4)2SO4 and 30µm MnCl2·4H2O were found to be optimal detection conditions. Interference by glucose, fructose, ethanol, and acetic acid in glycerol detection was studied. The observations indicated a promising enhancement in glycerol detection using the novel FeS-based glycerol sensing electrode compared to the conventional PQQ-based one. These findings support the premise that FeS-based bioanodes are capable of biosensing glycerol successfully and may be applicable for other enzymatic biosensors.

  1. Glycerol stress in Saccharomyces cerevisiae: Cellular responses and evolved adaptations.

    PubMed

    Mattenberger, Florian; Sabater-Muñoz, Beatriz; Hallsworth, John E; Fares, Mario A

    2017-03-01

    Glycerol synthesis is key to central metabolism and stress biology in Saccharomyces cerevisiae, yet the cellular adjustments needed to respond and adapt to glycerol stress are little understood. Here, we determined impacts of acute and chronic exposures to glycerol stress in S. cerevisiae. Glycerol stress can result from an increase of glycerol concentration in the medium due to the S. cerevisiae fermenting activity or other metabolic activities. Acute glycerol-stress led to a 50% decline in growth rate and altered transcription of more than 40% of genes. The increased genetic diversity in S. cerevisiae population, which had evolved in the standard nutrient medium for hundreds of generations, led to an increase in growth rate and altered transcriptome when such population was transferred to stressful media containing a high concentration of glycerol; 0.41 M (0.990 water activity). Evolution of S. cerevisiae populations during a 10-day period in the glycerol-containing medium led to transcriptome changes and readjustments to improve control of glycerol flux across the membrane, regulation of cell cycle, and more robust stress response; and a remarkable increase of growth rate under glycerol stress. Most of the observed regulatory changes arose in duplicated genes. These findings elucidate the physiological mechanisms, which underlie glycerol-stress response, and longer-term adaptations, in S. cerevisiae; they also have implications for enigmatic aspects of the ecology of this otherwise well-characterized yeast.

  2. Continual production of glycerol from carbon dioxide by Dunaliella tertiolecta.

    PubMed

    Chow, Yvonne Y S; Goh, Serena J M; Su, Ziheng; Ng, Daphne H P; Lim, Chan Yuen; Lim, Natalie Y N; Lin, Huixin; Fang, Lei; Lee, Yuan Kun

    2013-05-01

    Microalgae have high photosynthetic efficiencies and produce many valuable compounds from carbon dioxide. The Dunaliella genus accumulates glycerol, yet no commercial process currently exists for glycerol production from this microalga. Here it was found that in addition to intracellular accumulation, Dunaliella tertiolecta also releases glycerol into the external medium continuously, forming a large and stable carbon pool. The process is not affected by nutrient starvation or onset of cell death. Carbon dioxide was fixed at a constant rate, the bulk of it being channelled to extracellular glycerol (82%), resulting in enhanced photosynthetic carbon assimilation of 5 times that used for biomass production. The final extracellular glycerol concentration was 34 times the maximum concentration of intracellular glycerol; the latter declined further during cell death. Findings from this work will assist in the development of a bioconversion process to produce glycerol using D. tertiolecta without the need for cell harvest or disruption.

  3. Endocannabinoid regulation of nausea is mediated by 2-arachidonoylglycerol (2-AG) in the rat visceral insular cortex

    PubMed Central

    Sticht, Martin A.; Limebeer, Cheryl L.; Rafla, Benjamin R.; Abdullah, Rehab A.; Poklis, Justin L.; Ho, Winnie; Niphakis, Micah J.; Cravatt, Benjamin F.; Sharkey, Keith A.; Lichtman, Aron H.; Parker, Linda A.

    2015-01-01

    Cannabinoid (CB) agonists suppress nausea in humans and animal models; yet, their underlying neural substrates remain largely unknown. Evidence suggests that the visceral insular cortex (VIC) plays a critical role in nausea. Given the expression of CB1 receptors and the presence of endocannabinoids in this brain region, we hypothesized that the VIC endocannabinoid system regulates nausea. In the present study, we assessed whether inhibiting the primary endocannabinoid hydrolytic enzymes in the VIC reduces acute lithium chloride (LiCl)-induced conditioned gaping, a rat model of nausea. We also quantified endocannabinoid levels during an episode of nausea, and assessed VIC neuronal activation using the marker, c-Fos. Local inhibition of monoacylglycerol lipase (MAGL), the main hydrolytic enzyme of 2-arachidonylglycerol (2-AG), reduced acute nausea through a CB1 receptor mechanism, whereas inhibition of fatty acid amide hydrolase (FAAH), the primary catabolic enzyme of anandamide (AEA), was without effect. Levels of 2-AG were also selectively elevated in the VIC during an episode of nausea. Inhibition of MAGL robustly increased 2-AG in the VIC, while FAAH inhibition had no effect on AEA. Finally, we demonstrated that inhibition of MAGL reduced VIC Fos immunoreactivity in response to LiCl treatment. Taken together, these findings provide compelling evidence that acute nausea selectively increases 2-AG in the VIC, and suggests that 2-AG signaling within the VIC regulates nausea by reducing neuronal activity in this forebrain region. PMID:26541329

  4. Characterization of nanostructured TiO2:Ag films: structural and optical properties

    NASA Astrophysics Data System (ADS)

    Ivanova, T.; Harizanova, A.; Koutzarova, T.; Vertruyen, B.

    2016-10-01

    TiO2:Ag nanocomposites have been prepared by sol-gel method with varying silver concentration. Different technological approaches are employed to study the formation of Ag nanoparticles in titanium dioxide matrix. The obtained thin films are either thermally treated at temperatures from 300 to 600oC or UV irradiated for 15 minutes between layer deposition. XRD and FTIR studies reveal that Ag is incorporated in TiO2 films as nanoparticles and no Ag oxide phases are detected. Optical characterization performed by UV-VIS spectroscopy confirms the formation of silver nanoparticles. The influence of thermal treatment and UV radiation on the optical and structural properties is studied.

  5. Ultrasound assisted enzyme catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate.

    PubMed

    Waghmare, Govind V; Vetal, Mangesh D; Rathod, Virendra K

    2015-01-01

    The present work illustrates the transesterification of glycerol to glycerol carbonate (GlyC) from dimethyl carbonate (DMC) using commercial immobilized lipase (Novozym 435) under ultrasonic irradiation. The experiments were performed in a batch reactor placed in an ultrasonic water bath using a sequence of experimental protocol to evaluate the effects of temperature, molar ratios of substrates, enzyme loading, duty cycle and ultrasound power on the conversion of glycerol to GlyC. It has been found that ultrasound-assisted lipase-catalyzed transesterification of glycerol would be a potential alternative to conventional alkali-catalyzed method, as high conversion (99.75%) was obtained at mild operating conditions: molar ratio of DMC to glycerol 3:1, catalyst amount of 13% (w/w), lower power input (100W), duty cycle 50% and temperature (60°C) in a relatively short reaction time (4h) using Novozym 435 as catalyst. Ultrasound reduces the reaction time up to 4h as compared to conventional stirring method (14h) catalyzed by Novozym 435. The repeated use of the catalyst under the optimum experimental condition resulted in decay in both enzyme activity and product conversion.

  6. Biological Conversion of Glycerol to Ethanol by Enterobacter aerogenes

    NASA Astrophysics Data System (ADS)

    Nwachukwu, Raymond E. S.

    In a search to turn the economically and environmentally non-valuable "waste" streams of biodiesel production into a profitable byproduct, a mutant strain of Enterobacter aerogenes ATCC 13048 was developed by six-tube subculturing technique. This technique is based on the principle of adaptive evolution, and involved subculturing the bacterium in a tryptic soy broth without dextrose (TSB) containing specific glycerol and ethanol concentration for six consecutive times. Then, the six consecutive subculturing was repeated in a fresh TSB of higher glycerol and ethanol concentrations. A new mutant strain, E. aerogenes S012, which could withstand a combination of 200 g/l glycerol and 30 g/l ethanol concentrations, was developed. The wild and mutant strains were used for the fermentation of pure (P-) and recovered (R-) glycerol. Taguchi and full factorial methods of design of experiments were used to screen and optimize the important process factors that influence the microbial production of ethanol. A statistically sound regression model was used to establish the mathematical relationship between the process variables and ethanol production. Temperature of 38°C, agitation speed of 200 rpm, pH of 6.3-6.6, and microaerobic condition were the optimum process conditions. Different pretreatment methods to recover glycerol from the crude glycerol and the subsequent fermentation method showed that direct acidification using 85% H3PO4 was the best. The R-glycerol contained 51% pure glycerol and 21% methanol. The wild strain, E. aerogenes ATCC 13048, produced only 12 g/l and 12.8 g/l ethanol from 20 g/l P- and R-glycerol respectively, and could not utilize higher glycerol concentrations. The mutant, E. aerogenes S012, produced ethanol amount and yield of 43 g/l and 1.12 mol/mol-glycerol from P-glycerol, respectively within 96 h. It also produced ethanol amount and yield of 26.8 g/l and 1.07 mol/mol-glycerol, respectively, from R-glycerol within the same duration. In a

  7. The Ratio of 2-AG to Its Isomer 1-AG as an Intrinsic Fine Tuning Mechanism of CB1 Receptor Activation

    PubMed Central

    Dócs, Klaudia; Mészár, Zoltán; Gonda, Sándor; Kiss-Szikszai, Attila; Holló, Krisztina; Antal, Miklós; Hegyi, Zoltán

    2017-01-01

    Endocannabinoids are pleiotropic lipid messengers that play pro-homeostatic role in cellular physiology by strongly influencing intracellular Ca2+ concentration through the activation of cannabinoid receptors. One of the best-known endocannabinoid ‘2-AG’ is chemically unstable in aqueous solutions, thus its molecular rearrangement, resulting in the formation of 1-AG, may influence 2-AG-mediated signaling depending on the relative concentration and potency of the two isomers. To predict whether this molecular rearrangement may be relevant in physiological processes and in experiments with 2-AG, here we studied if isomerization of 2-AG has an impact on 2-AG-induced, CB1-mediated Ca2+ signaling in vitro. We found that the isomerization-dependent drop in effective 2-AG concentration caused only a weak diminution of Ca2+ signaling in CB1 transfected COS7 cells. We also found that 1-AG induces Ca2+ transients through the activation of CB1, but its working concentration is threefold higher than that of 2-AG. Decreasing the concentration of 2-AG in parallel to the prevention of 1-AG formation by rapid preparation of 2-AG solutions, caused a significant diminution of Ca2+ signals. However, various mixtures of the two isomers in a fix total concentration – mimicking the process of isomerization over time – attenuated the drop in 2-AG potency, resulting in a minor decrease in CB1 mediated Ca2+ transients. Our results indicate that release of 2-AG into aqueous medium is accompanied by its isomerization, resulting in a drop of 2-AG concentration and simultaneous formation of the similarly bioactive isomer 1-AG. Thus, the relative concentration of the two isomers with different potency and efficacy may influence CB1 activation and the consequent biological responses. In addition, our results suggest that 1-AG may play role in stabilizing the strength of cannabinoid signal in case of prolonged 2-AG dependent cannabinoid mechanisms. PMID:28265242

  8. The dual FAAH/MAGL inhibitor JZL195 has enhanced effects on endocannabinoid transmission and motor behavior in rats as compared to those of the MAGL inhibitor JZL184.

    PubMed

    Seillier, Alexandre; Dominguez Aguilar, David; Giuffrida, Andrea

    2014-09-01

    The biological actions of the endocannabinoids anandamide and 2-arachidonoyl glycerol (2-AG) are terminated by enzymatic hydrolysis of these lipids via fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), respectively. While several selective FAAH inhibitors have been developed and characterized in vitro and in vivo, none of the initial MAGL blockers have shown adequate potency and specificity for in vivo applications. More recently, a selective MAGL inhibitor, JZL184, has been shown to produce a long-lasting elevation of brain 2-AG, as well as cannabinoid-like behavioral responses in mice. However, its effectiveness in rats remains controversial. Indeed, although JZL184 can elicit behavioral responses that are mediated, at least in part, via activation of cannabinoid CB1 receptors, several reports indicate that this compound does not alter 2-AG levels in this species. In this study we compared the behavioral and neurochemical effects of JZL 184 with those of the dual FAAH/MAGL inhibitor JZL195, and showed that systemic administration of the former can selectively elevate brain 2-AG in rats and produce motor suppression through a CB1-independent mechanism. These findings indicate that, despite its lower potency against rat MAGL, JZL184 can be used to enhance 2-AG transmission and elicit behavioral responses in rodents.

  9. Reduction of glycerol production to improve ethanol yield in an engineered Saccharomyces cerevisiae using glycerol as a substrate.

    PubMed

    Yu, Kyung Ok; Kim, Seung Wook; Han, Sung Ok

    2010-10-15

    Ethanol plays an important role in substituting the increasingly limited oil as the high-value, renewable fuel. In our previous studies, we successfully established the conversion of glycerol to ethanol by overexpression of pGcyaDak with pGup1Cas in Saccharomyces cerevisiae. In addition to increasing ethanol production using glycerol as substrate, we minimized the synthesis of glycerol, which is the main by-product in ethanol fermentation processing. The glycerol production pathway was impaired by deletion of the genes FPS1 and GPD2. Strains deleted for both FPS1 and GPD2 reduce glycerol production and become highly sensitive to osmotic stress. We provide osmotic protection in YPH499fps1Δgpd2Δ by overexpression of Gup1. In this study, S. cerevisiae using glycerol as substrate was modified through one-step gene disruption for redirection of glycerol carbon flux into ethanol by the deletion of two glycerol production genes, FPS1 and GPD2. The overall ethanol production in the modified strain YPH499fps1Δgpd2Δ (pGcyaDak, pGupCas) was about 4.4 gl⁻¹. These results demonstrate the possibility of providing protection against osmotic stress while simultaneously increasing ethanol and reducing glycerol production in S. cerevisiae strains using glycerol as a carbon source.

  10. Protein phase behavior and crystallization: Effect of glycerol

    NASA Astrophysics Data System (ADS)

    Sedgwick, H.; Cameron, J. E.; Poon, W. C. K.; Egelhaaf, S. U.

    2007-09-01

    Glycerol is widely used as an additive to stabilize proteins in aqueous solution. We have studied the effect of up to 40wt% glycerol on the crystallization of lysozyme from brine. As the glycerol concentration increased, progressively larger amounts of salt were needed to crystallize the protein. Like previous authors, we interpret this as evidence for glycerol changing the interaction between lysozyme molecules. We quantitatively model the interprotein interaction using a Derjaguin-Landau-Verwey-Overbeek potential. We find that the effect of glycerol can be entirely accounted for by the way it modifies the dielectric constant and refractive index of the solvent. Quantifying the interprotein interaction by the second virial coefficient, B2, we find a universal crystallization boundary for all glycerol concentrations.

  11. Protein phase behavior and crystallization: effect of glycerol.

    PubMed

    Sedgwick, H; Cameron, J E; Poon, W C K; Egelhaaf, S U

    2007-09-28

    Glycerol is widely used as an additive to stabilize proteins in aqueous solution. We have studied the effect of up to 40 wt % glycerol on the crystallization of lysozyme from brine. As the glycerol concentration increased, progressively larger amounts of salt were needed to crystallize the protein. Like previous authors, we interpret this as evidence for glycerol changing the interaction between lysozyme molecules. We quantitatively model the interprotein interaction using a Derjaguin-Landau-Verwey-Overbeek potential. We find that the effect of glycerol can be entirely accounted for by the way it modifies the dielectric constant and refractive index of the solvent. Quantifying the interprotein interaction by the second virial coefficient, B(2), we find a universal crystallization boundary for all glycerol concentrations.

  12. Glycerol metabolism promotes biofilm formation by Pseudomonas aeruginosa.

    PubMed

    Scoffield, Jessica; Silo-Suh, Laura

    2016-08-01

    Pseudomonas aeruginosa causes persistent infections in the airways of cystic fibrosis (CF) patients. Airway sputum contains various host-derived nutrients that can be utilized by P. aeruginosa, including phosphotidylcholine, a major component of host cell membranes. Phosphotidylcholine can be degraded by P. aeruginosa to glycerol and fatty acids to increase the availability of glycerol in the CF lung. In this study, we explored the role that glycerol metabolism plays in biofilm formation by P. aeruginosa. We report that glycerol metabolism promotes biofilm formation by both a chronic CF isolate (FRD1) and a wound isolate (PAO1) of P. aeruginosa. Moreover, loss of the GlpR regulator, which represses the expression of genes involved in glycerol metabolism, enhances biofilm formation in FRD1 through the upregulation of Pel polysaccharide. Taken together, our results suggest that glycerol metabolism may be a key factor that contributes to P. aeruginosa persistence by promoting biofilm formation.

  13. Fungal biotransformation of crude glycerol into malic acid.

    PubMed

    West, Thomas P

    2015-01-01

    Malic acid production from the biodiesel coproduct crude glycerol by Aspergillus niger ATCC 9142, ATCC 10577 and ATCC 12846 was observed to occur with the highest malic acid level acid being produced by A. niger ATCC 12846. Fungal biomass production from crude glycerol was similar, but ATCC 10577 produced the highest biomass. Fungal biotransformation of crude glycerol into the commercially valuable organic acid malic acid appeared feasible.

  14. Effect of Ambient Temperature on the Toxicity of Palmitoyl Glycerol.

    DTIC Science & Technology

    1985-11-25

    consumed or its rate of absorption. Similarly, there were no differences between those fed the palmitoyl glycerol diet with or without safflower oil...level. circulating neurotensin in mice fed the palmitoyl glycerol diet wit" or with safflower oil by radioimmunoassay. We found no differe between...involvement, we injected prostaglandin E2 intracisternally into mice fed palmitoyl glycerol with or without safflower oil. This hormone had no effect on

  15. Preparation of echinus-like SiO2@Ag structures with the aid of the HCP phase.

    PubMed

    Liu, Tao; Li, Dongsheng; Yang, Deren; Jiang, Minhua

    2011-05-14

    A novel echinus-like hybrid structure composed of a SiO(2)@Ag core-shell and many silver nanorods was synthesized. These silver rods have a rare HCP structure, while the initial silver nuclei have a FCC structure. The rapid and free growth of silver nuclei resulted in the appearance of the HCP phase.

  16. Effect of Erbium on the Photocatalytic Activity of TiO2 /Ag Nanocomposites under Visible Light Irradiation.

    PubMed

    Prakash, Natarajan; Karthikeyan, Rajan; Thangaraju, Dheivasigamani; Navaneethan, Mani; Arivanandhan, Mukannan; Koyama, Tadanobu; Hayakawa, Yasuhiro

    2015-10-05

    Erbium co-doped TiO2 /Ag catalysts are synthesized by using a simple, one-step solvothermal method and characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Raman analysis, X-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy. The catalysts exhibit anatase crystal structures with increased visible light absorption compared with pure TiO2 . Enhanced photocatalytic activity is observed with Er co-doped TiO2 /Ag nanocomposites for Rhodamine B degradation under visible light irradiation. The photocatalytic activity of 1 % Er co-doped TiO2 /Ag is much higher than that of TiO2 /Ag, TiO2 /Er, pure TiO2 , and commercial Degussa P25. The kinetics of the degradation process are studied and the pseudo-first-order rate constant (k) and half-life time (t1/2 ) of the reaction are calculated. The enhanced activity might be accredited to the efficient separation of electron-hole pairs by silver and higher visible light absorption of TiO2 induced by Er.

  17. Fermentation of xylose to glycerol by Rhizopus javanicus

    SciTech Connect

    Lu, Z.; Yang, C.W.; Tsao, G.T.

    1995-12-31

    Glycerol production from xylose fermentation using Rhizopus javanicus (ATCC 22581) has been investigated in shake flasks. The medium composition (xylose concentration, nitrogen sources), aeration rate, and temperature have been found to affect the accumulation and yield of glycerol. Some of these effects are explained in terms of the critical parameters, osmotic pressure, and dissolved oxygen levels in the medium. Relatively high glycerol yields and concentrations have been obtained at high sugar concentration with high level of aeration at room temperature. The addition of polyethylene glycol or sulfite can improve the yield and accumulation of glycerol.

  18. Fermentation of crude glycerol from biodiesel production by Clostridium pasteurianum.

    PubMed

    Jensen, Torbjørn Olshøj; Kvist, Thomas; Mikkelsen, Marie Just; Christensen, Peter Vittrup; Westermann, Peter

    2012-05-01

    Clostridium pasteurianum can utilize glycerol as the sole carbon source for the production of butanol and 1,3-propanediol. Crude glycerol derived from biodiesel production has been shown to be toxic to the organism even in low concentrations. By examination of different pretreatments we found that storage combined with activated stone carbon addition facilitated the utilization of crude glycerol. A pH-controlled reactor with in situ removal of butanol by gas stripping was used to evaluate the performance. The fermentation pattern on pretreated crude glycerol was quite similar to that on technical grade glycerol. C. pasteurianum was able to utilize 111 g/l crude glycerol. The average consumption rate was 2.49 g/l/h and maximum consumption rate was 4.08 g/l/h. At the maximal glycerol consumption rate butanol was produced at 1.3 g/l/h. These rates are higher than those previously reported for fermentations on technical grade glycerol by the same strain. A process including pretreatment and subsequent fermentation of the crude glycerol could be usable for industrial production of butanol by C. pasteurianum.

  19. Photosynthetic production of glycerol by a recombinant cyanobacterium.

    PubMed

    Savakis, Philipp; Tan, Xiaoming; Du, Wei; Branco dos Santos, Filipe; Lu, Xuefeng; Hellingwerf, Klaas J

    2015-02-10

    Cyanobacteria are prokaryotic organisms capable of oxygenic photosynthesis. Glycerol is an important commodity chemical. Introduction of phosphoglycerol phosphatase 2 from Saccharomyces cerevisiae into the model cyanobacterium Synechocystis sp. PCC6803 resulted in a mutant strain that produced a considerable amount of glycerol from light, water and COPhotosynthetic production . Mild salt stress (200 mM NaCl) on the cells led to an increase of the extracellular glycerol concentration of more than 20%. Under these conditions the mutant accumulated glycerol to an extracellular concentration of 14.3 mM after 17 days of culturing.

  20. Rotation of ultrasonically levitated glycerol drops

    NASA Technical Reports Server (NTRS)

    Biswas, A.; Leung, E. W.; Trinh, E. H.

    1991-01-01

    Ultrasonic levitation is used to suspend single millimeter-size glycerol drops in a rectangular chamber. Audio-frequency laterally standing waves set up in the chamber are used to torque the suspended drops. The shape evolution of the drop under the combined effect of centrifugal forces and the acoustic radiation stress, along with its angular velocity are monitored, using video imaging and light scattering techniques. The results show good qualitative agreement with the theoretically predicted shape evolution as a function of angular velocity.

  1. Synthesis of antibacterial film CTS/PVP/TiO2/Ag for drinking water system.

    PubMed

    Zhang, Liang; Bai, Xue; Tian, Hua; Zhong, Lvling; Ma, Cailian; Zhou, Yuanzhen; Chen, Shuangli; Li, Dongliang

    2012-08-01

    A CTS/PVP/TiO2/Ag functional film was prepared as an antibacterial composite used in storing drinking water. The orthogonal experiment showed that the optimal conditions for preparing membranes with best antibacterial activity and tensile strength are c(AgNO3)=0.08%, c(TiO2)=0.20%, c(CTS)=2.25%, and c(PVP)=3.00%. The FT-IR spectrum implies that hydrogen bands are formed between acetyl in PVP and hydroxyl in CTS molecule, and -NH and -OH of CTS have some interactions with sliver nano-particles (nano-Ags) which were reduced in situ. The SEM images show that the TiO2 particles are displayed on the surface and embedded in the film. And nano-Ags are further proved through XRD and SEM images. The DSC curves show that the film has a favorable compatibility and heat stability. In application study, it is proved that this film has sustainable antibacterial activity and is safe in use.

  2. Electrochemical depositions of fluorohydroxyapatite doped by Cu2+, Zn2+, Ag+ on stainless steel substrates

    NASA Astrophysics Data System (ADS)

    Bir, F.; Khireddine, H.; Touati, A.; Sidane, D.; Yala, S.; Oudadesse, H.

    2012-07-01

    Fluoridated hydroxyapatite (FHA, Ca10(PO4)6(OH)2-xFx where 0 < x < 2 is the degree of fluoridation) and inorganic ions (Zn2+, Cu2+, Ag+) substituted fluoridated hydroxyapatite coatings (M-FHA) were deposited on the surface of medical grade 316L stainless steel samples by electrochemical deposition technique. The FHA coatings were co-substituted with antibacterial ions (Zn2+, Cu2+ or Ag+) by co-precipitation and ion-exchange methods. Characterization studies of coatings from X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDX) showed that the obtained layers are monophase crystals FHA and did not contain any discernible crystalline impurity. The particles of all samples are of nano size that gives thin layers. The surface morphology, microstructure and Ca/P atomic ratio of the FHA coatings can be regulated by varying electrolyte temperature. This later affects the porosity of the coating surface and the chemical compositions of the deposits. Quantitative elemental analysis indicates that the copper, zinc and silver ions are incorporated into the Fluorohydroxyapatite. The antimicrobial effects of doped fluorohydroxyapatite coatings against pathogen bacterial strains Staphylococcus aureus were tested in liquid media. The results are promising and demonstrated that all doped FHA samples exhibit excellent antimicrobial activity "in vitro" against the microorganism, so the antimicrobial properties of the coatings developed are improved.

  3. Effects of glycerol on enzymatic hydrolysis and ethanol production using sugarcane bagasse pretreated by acidified glycerol solution.

    PubMed

    Zhang, Zhanying; Wong, Heng H; Albertson, Peter L; Harrison, Mark D; Doherty, William O S; O'Hara, Ian M

    2015-09-01

    In this study, for the first time the effects of glycerol on enzymatic hydrolysis and ethanol fermentation were investigated. Enzymatic hydrolysis was inhibited slightly with 2.0 wt% glycerol, leading to reduction in glucan digestibility from 84.9% without glycerol to 82.9% (72 h). With 5.0 wt% and 10.0 wt% glycerol, glucan digestibility was reduced by 4.5% and 11.0%, respectively. However, glycerol did not irreversibly inhibit cellulase enzymes. Ethanol fermentation was not affected by glycerol up to 5.0 wt%, but was inhibited slightly at 10.0 wt% glycerol, resulting in reduction in ethanol yield from 86.0% in the absence of glycerol to 83.7% (20 h). Based on the results of laboratory and pilot-scale experiments, it was estimated that 0.142 kg ethanol can be produced from 1.0 kg dry bagasse (a glucan content of 38.0%) after pretreatment with acidified glycerol solution.

  4. Free-energy studies reveal a possible mechanism for oxidation-dependent inhibition of MGL

    PubMed Central

    Scalvini, Laura; Vacondio, Federica; Bassi, Michele; Pala, Daniele; Lodola, Alessio; Rivara, Silvia; Jung, Kwang-Mook; Piomelli, Daniele; Mor, Marco

    2016-01-01

    The function of monoacylglycerol lipase (MGL), a key actor in the hydrolytic deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2AG), is tightly controlled by the cell’s redox state: oxidative signals such as hydrogen peroxide suppress MGL activity in a reversible manner through sulfenylation of the peroxidatic cysteines, C201 and C208. Here, using as a starting point the crystal structures of human MGL (hMGL), we present evidence from molecular dynamics and metadynamics simulations along with high-resolution mass spectrometry studies indicating that sulfenylation of C201 and C208 alters the conformational equilibrium of the membrane-associated lid domain of MGL to favour closed conformations of the enzyme that do not permit the entry of substrate into the active site. PMID:27499063

  5. Ruminal fermentation of propylene glycol and glycerol.

    PubMed

    Trabue, Steven; Scoggin, Kenwood; Tjandrakusuma, Siska; Rasmussen, Mark A; Reilly, Peter J

    2007-08-22

    Bovine rumen fluid was fermented anaerobically with 25 mM R-propylene glycol, S-propylene glycol, or glycerol added. After 24 h, all of the propylene glycol enantiomers and approximately 80% of the glycerol were metabolized. Acetate, propionate, butyrate, valerate, and caproate concentrations, in decreasing order, all increased with incubation time. Addition of any of the three substrates somewhat decreased acetate formation, while addition of either propylene glycol increased propionate formation but decreased that of butyrate. R- and S-propylene glycol did not differ significantly in either their rates of disappearance or the products formed when they were added to the fermentation medium. Fermentations of rumen fluid containing propylene glycol emitted the sulfur-containing gases 1-propanethiol, 1-(methylthio)propane, methylthiirane, 2,4-dimethylthiophene, 1-(methylthio)-1-propanethiol, dipropyl disulfide, 1-(propylthio)-1-propanethiol, dipropyl trisulfide, 3,5-diethyl-1,2,4-trithiolane, 2-ethyl-1,3-dithiane, and 2,4,6-triethyl-1,3,5-trithiane. Metabolic pathways that yield each of these gases are proposed. The sulfur-containing gases produced during propylene glycol fermentation in the rumen may contribute to the toxic effects seen in cattle when high doses are administered for therapeutic purposes.

  6. Biodegradation of Glycerol Trinitrate and Pentaerythritol Tetranitrate by Agrobacterium radiobacter

    PubMed Central

    White, G. F.; Snape, J. R.; Nicklin, S.

    1996-01-01

    Bacteria capable of metabolizing highly explosive and vasodilatory glycerol trinitrate (GTN) were isolated under aerobic and nitrogen-limiting conditions from soil, river water, and activated sewage sludge. One of these strains (from sewage sludge) chosen for further study was identified as Agrobacterium radiobacter subgroup B. A combination of high-pressure liquid chromatography and nuclear magnetic resonance analyses of the culture medium during the growth of A. radiobacter on basal salts-glycerol-GTN medium showed the sequential conversion of GTN to glycerol dinitrates and glycerol mononitrates. Isomeric glycerol 1,2-dinitrate and glycerol 1,3-dinitrate were produced simultaneously and concomitantly with the disappearance of GTN, with significant regioselectivity for the production of the 1,3-dinitrate. Dinitrates were further degraded to glycerol 1- and 2-mononitrates, but mononitrates were not biodegraded. Cells were also capable of metabolizing pentaerythritol tetranitrate, probably to its trinitrate and dinitrate analogs. Extracts of broth-grown cells contained an enzyme which in the presence of added NADH converted GTN stoichiometrically to nitrite and the mixture of glycerol dinitrates. The specific activity of this enzyme was increased 160-fold by growth on GTN as the sole source of nitrogen. PMID:16535244

  7. 40 CFR 721.10323 - Glycerol fatty acid ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Glycerol fatty acid ester (generic... Specific Chemical Substances § 721.10323 Glycerol fatty acid ester (generic). (a) Chemical substance and... acid ester (PMN P-03-248) is subject to reporting under this section for the significant new...

  8. 40 CFR 721.10323 - Glycerol fatty acid ester (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Glycerol fatty acid ester (generic... Specific Chemical Substances § 721.10323 Glycerol fatty acid ester (generic). (a) Chemical substance and... acid ester (PMN P-03-248) is subject to reporting under this section for the significant new...

  9. 40 CFR 721.10323 - Glycerol fatty acid ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Glycerol fatty acid ester (generic... Specific Chemical Substances § 721.10323 Glycerol fatty acid ester (generic). (a) Chemical substance and... acid ester (PMN P-03-248) is subject to reporting under this section for the significant new...

  10. Thermal and Structural Properties of Silk Biomaterials Plasticized by Glycerol.

    PubMed

    Brown, Joseph E; Davidowski, Stephen K; Xu, Dian; Cebe, Peggy; Onofrei, David; Holland, Gregory P; Kaplan, David L

    2016-12-12

    The molecular interactions of silk materials plasticized using glycerol were studied, as these materials provide options for biodegradable and flexible protein-based systems. Plasticizer interactions with silk were analyzed by thermal, spectroscopic, and solid-state NMR analyses. Spectroscopic analysis implied that glycerol was hydrogen bonded to the peptide matrix, but may be displaced with polar solvents. Solid-state NMR indicated that glycerol induced β-sheet formation in the dried silk materials, but not to the extent of methanol treatment. Fast scanning calorimetry suggested that β-sheet crystal formation in silk-glycerol films appeared to be less organized than in the methanol treated silk films. We propose that glycerol may be simultaneously inducing and interfering with β-sheet formation in silk materials, causing some improper folding that results in less-organized silk II structures even after the glycerol is removed. This difference, along with trace residual glycerol, allows glycerol extracted silk materials to retain more flexibility than methanol processed versions.

  11. Unilamellar DMPC vesicles in aqueous glycerol: preferential interactions and thermochemistry.

    PubMed

    Westh, Peter

    2003-01-01

    Glycerol is accumulated in response to environmental stresses in a diverse range of organisms. Understanding of favorable in vivo effects of this solute requires insight into its interactions with biological macromolecules, and one access to this information is the quantification of so-called preferential interactions in glycerol-biopolymer solutions. For model membrane systems, preferential interactions have been discussed, but not directly measured. Hence, we have applied a new differential vapor pressure equipment to quantify the isoosmotic preferential binding parameter, Gamma( micro 1), for systems of unilamellar vesicles of DMPC in aqueous glycerol. It is found that Gamma( micro 1) decreases linearly with the glycerol concentration with a slope of -0.14 +/- 0.014 per molal. This implies that glycerol is preferentially excluded from the membrane-solvent interface. Calorimetric investigations of the same systems showed that the glycerol-DMPC interactions are weakly endothermic, and the temperature of the main phase transition increases slightly (0.16 degrees C per molal) with the glycerol concentration. The results are discussed with respect to a molecular picture which takes into account both the partitioning of glycerol into the membrane and the preferential exclusion from the hydration layer, and it is concluded that the latter effect contributes about four times stronger than the former to the net interaction.

  12. The Acrylation of Glycerol: a Precursor to Functionalized Lipids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Didecanoylacryloylglycerol was synthesized from decanoic and acrylic acids and glycerol using K2O as catalyst. This reaction was carried out in hexane in a closed stainless steel reactor at 200°C for 5h. The reactants were added in a 1:3:4 glycerol:decanoic acid:acrylic acid molar ratio. The resu...

  13. Synthesis and applications of {sup 13}C glycerol

    SciTech Connect

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III

    1994-12-01

    Due in part to the use of labeled glycerol for the {sup 13}C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide ({approximately}53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific {sup 13}C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of {sup 13}C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of {sup 13}C-labeled DHA to DHAP. We are especially interested in {sup 13}C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids.

  14. Fabrication of a glycerol from CO2 reaction system, supplement

    NASA Technical Reports Server (NTRS)

    Weiss, A. H.

    1973-01-01

    The fabrication, installation, and testing of a glycerol hydrogenation and a CO2 hydrogenation - CH4 partial oxidation units are reported. The glycerol system proved to be operational while the CO2 system was installed but not bought on operational steam.

  15. 75 FR 71556 - Polyoxyalkylated Glycerol Fatty Acid Esters; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-24

    ... AGENCY 40 CFR Part 180 Polyoxyalkylated Glycerol Fatty Acid Esters; Tolerance Exemption AGENCY... from the requirement of a tolerance for residues of polyoxyalkylated glycerol fatty acid esters; the... unsaturated, fatty acids containing up to 15% water by weight reacted with a minimum of three moles of...

  16. Conserved family of glycerol kinase loci in Drosophila melanogaster

    PubMed Central

    Martinez Agosto, Julian A.; McCabe, Edward R.B.

    2009-01-01

    Glycerol kinase (GK) is an enzyme that catalyzes the formation of glycerol 3-phosphate from ATP and glycerol, the rate-limiting step in glycerol utilization. We analyzed the genome of the model organism Drosophila melanogaster and identified five GK orthologs, including two loci with sequence homology to the mammalian Xp21 GK protein. Using a combination of sequence analysis and evolutionary comparisons of orthologs between species, we characterized functional domains in the protein required for GK activity. Our findings include additional conserved domains that suggest novel nuclear and mitochondrial functions for glycerol kinase in apoptosis and transcriptional regulation. Investigation of GK function in Drosophila will inform us about the role of this enzyme in development and will provide us with a tool to examine genetic modifiers of human metabolic disorders. PMID:16545593

  17. Glycerol, an underestimated flavor precursor in the Maillard reaction.

    PubMed

    Smarrito-Menozzi, Candice; Matthey-Doret, Walter; Devaud-Goumoens, Stéphanie; Viton, Florian

    2013-10-30

    The objective of the present work was to investigate in depth the role of glycerol in Maillard reactions and its potential to act as an active flavor precursor. Reactions using isotopically labeled compounds (various reducing sugars, proline, and glycerol) unambiguously demonstrated that, in addition to its role of solvent, glycerol actively contributes to the formation of proline-specific compounds in Maillard model systems. Additionally, rhamnose and fucose/proline/glycerol systems generated the 2-propionyl-1(3),4,5,6-tetrahydropyridines, known for their roasty, popcorn aroma. Their formation from such systems is unprecedented. The results presented here have direct implications for flavor generation during thermal processing of foods containing glycerol, which is a ubiquitous food ingredient and an underestimated flavor precursor.

  18. Microbial conversion of glycerol to 1,3-propanediol

    SciTech Connect

    Zeng, A.P.; Biebl, H.; Deckwer, W.D.

    1996-10-01

    Glycerol is a byproduct from the soap and detergent industry and possibly from future biodiesel plants. The conversion of glycerol to 1,3-propanediol (PD) is of industrial interest due to the potential use of PD for the synthesis of polyesters. We have been studying the microbial conversion of glycerol to PD with work ranging from strain isolation, medium optimization, pathway analysis, product formation kinetics and growth modeling, downstream processing and reactor scale-up (up to 2000 1). PD yields of nearly 100% of the theoretical maximum (0.72 mol/mol glycerol) and final product concentrations of about 65 g/l were achieved with both Klebsiella pneumoniae and Clostridium butyricum. In addition to summarizing our experimental results the advances of bioconversion of glycerol will be reviewed in this presentation, with emphasis on discussing further research and development needs in this area. Results of process engineering and cost analysis will also be presented.

  19. Photonic crystals with SiO2-Ag ``post-cap'' nanostructure coatings for surface enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kim, Seok-min; Zhang, Wei; Cunningham, Brian T.

    2008-10-01

    We demonstrate that the resonant near fields of a large-area replica molded photonic crystal (PC) slab can efficiently couple light from a laser to SiO2-Ag "post-cap" nanostructures deposited on the PC surface by a glancing angle evaporation technique for achieving high surface enhanced Raman spectroscopy (SERS) enhancement factor. To examine the feasibility of the PC-SERS substrate, the simulated electric field around individual Ag particles and the measured Raman spectrum of trans-1,2-bis(4pyridyl)ethane on the PC-SERS substrate were compared with those from an ordinary glass substrate coated with the same SiO2-Ag nanostructures.

  20. Beam focusing from double subwavelength slits surrounded by Ag/SiO2/Ag tri-layer gratings

    NASA Astrophysics Data System (ADS)

    Su, Wei; Zhou, Chong; Zheng, Gaige; Li, Xiangyin

    2016-12-01

    A silver(Ag)/SiO2/Ag tri-layer grating structure with double slits for beam focusing has been proposed. Compared with the metal/dielectric double-layer grating-based structure, the focusing efficiency of our proposed structure can be greatly enhanced. Numerical simulations using the finite-different time-domain (FDTD) method verify that the focal length and deflection angle can be controlled by adjusting the refractive indexes of dielectric mediums in the two slits.

  1. Liquefaction of lignin by polyethyleneglycol and glycerol.

    PubMed

    Jin, Yanqiao; Ruan, Xuemin; Cheng, Xiansu; Lü, Qiufeng

    2011-02-01

    Enzymatic hydrolysis lignin (EHL), isolated from the enzymatic hydrolysis residues of the biomass, was liquefied using the mixed solvents of polyethyleneglycol (PEG) and glycerol at the temperature of 130-170°C with sulfuric acid as a catalyst. The influences of liquefaction parameters, such as the molecular weight of PEG, mass ratio of sulfuric acid to EHL, liquefaction temperature and time, and mass ratio of liquid (liquefying cosolvent) to solid (EHL) on the residue content and hydroxyl number were discussed. The FT-IR spectrum result showed that the liquefaction product of EHL was polyether polyol. The hydroxyl number of the liquefaction product was 80-120 mgKOH/g higher than that of PEG.

  2. Renewable Chemicals: Dehydroxylation of Glycerol and Polyols

    PubMed Central

    ten Dam, Jeroen; Hanefeld, Ulf

    2011-01-01

    The production of renewable chemicals is gaining attention over the past few years. The natural resources from which they can be derived in a sustainable way are most abundant in sugars, cellulose and hemicellulose. These highly functionalized molecules need to be de-functionalized in order to be feedstocks for the chemical industry. A fundamentally different approach to chemistry thus becomes necessary, since the traditionally employed oil-based chemicals normally lack functionality. This new chemical toolbox needs to be designed to guarantee the demands of future generations at a reasonable price. The surplus of functionality in sugars and glycerol consists of alcohol groups. To yield suitable renewable chemicals these natural products need to be defunctionalized by means of dehydroxylation. Here we review the possible approaches and evaluate them from a fundamental chemical aspect. PMID:21887771

  3. Molecular dynamics simulation study of the effect of glycerol dialkyl glycerol tetraether hydroxylation on membrane thermostability.

    PubMed

    Huguet, Carme; Fietz, Susanne; Rosell-Melé, Antoni; Daura, Xavier; Costenaro, Lionel

    2017-02-16

    Archaeal tetraether membrane lipids span the whole membrane width and present two C40 isoprenoid chains bound by two glycerol groups (or one glycerol and calditol). These lipids confer stability and maintain the membrane fluidity in mesophile to extremophile environments, making them very attractive for biotechnological applications. The isoprenoid lipid composition in archaeal membranes varies with temperature, which has placed these lipids in the focus of paleo-climatological studies for over a decade. Non-hydroxylated isoprenoid archaeal lipids are typically used as paleo-thermometry proxies, but recently identified hydroxylated (OH) derivatives have also been proposed as temperature proxies. The relative abundance of hydroxylated lipids increases at lower temperatures, but the physiological function of the OH moiety remains unknown. Here we present molecular dynamics simulations of membranes formed by the acyclic glycerol-dialkyl-glycerol-tetraether caldarchaeol (GDGT-0), the most widespread archaeal core lipid, and its mono-hydroxylated variant (OH-GDGT-0) to better understand the physico-chemical properties conferred to the membrane by this additional moiety. The molecular dynamics simulations indicate that the additional OH group forms hydrogen bonds mainly with the sugar moieties of neighbouring lipids and with water molecules, effectively increasing the size of the polar headgroups. The hydroxylation also introduces local disorder that propagates along the entire alkyl chains, resulting in a slightly more fluid membrane. These changes would help to maintain trans-membrane transport in cold environments, explaining why the relative abundance of hydroxylated Archaea lipids increases at lower temperatures. The in silico approach aids to understand the underlying physiological mechanisms behind the hydroxylated lipid based paleo-thermometer recently proposed.

  4. Fabrication of TiO2/Ag2O heterostructure with enhanced photocatalytic and antibacterial activities under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Bingkun; Mu, Lilong; Han, Bing; Zhang, Jingtao; Shi, Hengzhen

    2017-02-01

    TiO2/Ag2O heterostructure prepared by a facile in situ precipitation route was used as an effective visible light-driven photocatalyst for degradation of methylene blue (MB) and inactivation of E. coli. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed that Ag2O nanoparticles were well distributed on the surface of TiO2 microspheres. The TiO2/Ag2O composite with optimal mass ratio of TiO2 and Ag2O displayed extremely good photodegradation ability and antibacterial capability under visible light irradiation, which was mainly ascribed to the synergistic effect between Ag2O and TiO2, including highly dispersed smaller Ag2O particles, increased visible light absorption and efficient separation of photo-induced charge carriers. Meanwhile, the roles of the radical species in the photocatalysis process were investigated. Our results showed that the TiO2/Ag2O could be used as a dual functional material in water treatment of removing the organic pollutant and killing the bacterium at the same time.

  5. Facile one-pot synthesis of uniform TiO2-Ag hybrid hollow spheres with enhanced photocatalytic activity.

    PubMed

    Wang, Sunli; Qian, Huanhuan; Hu, Yong; Dai, Wei; Zhong, Yijun; Chen, Jiafu; Hu, Xiao

    2013-01-28

    TiO(2)-Ag hybrid hollow spheres (about 700 nm in diameter) with a highly uniform morphology and good structural stability were facilely prepared via a one-pot hydrothermal method, using carbon spheres as templates followed by an annealing treatment. Through this route, the as-prepared hybrid hollow spheres preserved the uniformity of the initial carbon sphere templates and the loading amount of the Ag nanocrystals can be conveniently varied or controlled by the concentration of the Ag precursor. The investigation of the photocatalytic ability demonstrated that the as-prepared TiO(2)-Ag hybrid hollow spheres possess excellent photocatalytic activity, superior to commercial TiO(2) nanoparticles (Degussa P25), for the degradation of rhodamine B (RhB) and methyl orange (MO) dyes under visible-light illumination. Furthermore, the ˙OH radicals formed during photocatalysis with different Ag content hybrids were revealed by means of a terephthalic acid fluorescence probe method, which uncovers that the Ag content in the TiO(2)-Ag hybrids was crucial to obtain an optimal synergistic effect between the Ag and TiO(2) for the degradation of organic pollutants. Accordingly, the optimum matching for the best photocatalytic activity was investigated thoroughly and a reasonable mechanism was also proposed.

  6. Design and analysis of biorefineries based on raw glycerol: addressing the glycerol problem.

    PubMed

    Posada, John A; Rincón, Luis E; Cardona, Carlos A

    2012-05-01

    Glycerol as a low-cost by-product of the biodiesel industry can be considered a renewable building block for biorefineries. In this work, the conversion of raw glycerol to nine added-value products obtained by chemical (syn-gas, acrolein, and 1,2-propanediol) or bio-chemical (ethanol, 1,3-propanediol, d-lactic acid, succinic acid, propionic acid, and poly-3-hydroxybutyrate) routes were considered. The technological schemes for these synthesis routes were designed, simulated, and economically assessed using Aspen Plus and Aspen Icarus Process Evaluator, respectively. The techno-economic potential of a glycerol-based biorefinery system for the production of fuels, chemicals, and plastics was analyzed using the commercial Commercial Sale Price/Production Cost ratio criteria, under different production scenarios. More income can be earned from 1,3-propanediol and 1,2-propanediol production, while less income would be obtained from hydrogen and succinic acid. This analysis may be useful mainly for biodiesel producers since several profitable alternatives are presented and discussed.

  7. The fate of glycerol entering the rumen of dairy cows and sheep.

    PubMed

    Werner Omazic, A; Kronqvist, C; Zhongyan, L; Martens, H; Holtenius, K

    2015-04-01

    This study investigated the fate of glycerol entering the rumen, in particular whether glycerol could be absorbed across the rumen epithelium. Three non-lactating rumen-fistulated cows were used to calculate the overall disappearance rate of glycerol in vivo and evaluate the rate of ruminal glycerol absorption. Rumen epithelial tissues isolated from sheep were used to characterise glycerol transport properties. The rate of rumen microbial degradation of glycerol was then studied in an in vitro system under anaerobic and thermo-regulated conditions. The results showed that glycerol can be absorbed from the rumen in significant amounts. The fractional rate of absorption of glycerol was not affected by variations in glycerol concentration in the buffer solution in the in vivo study. The glycerol absorption apparently occurred largely by passive diffusion and was probably not facilitated by carriers. Glycerol also disappeared via microbial digestion and outflow from the rumen through the omasal orifice.

  8. Endocannabinoid Modulation of Predator Stress-Induced Long-Term Anxiety in Rats

    PubMed Central

    Lim, James; Igarashi, Miki; Jung, Kwang-Mook; Butini, Stefania; Campiani, Giuseppe; Piomelli, Daniele

    2016-01-01

    Individuals who experience life-threatening psychological trauma are at risk of developing a series of chronic neuropsychiatric pathologies that include generalized anxiety, depression, and drug addiction. The endocannabinoid system has been implicated in the modulation of these responses by regulating the activity of the amygdala and the hypothalamic–pituitary–adrenal axis. However, the relevance of this signaling complex to the long-term consequences of traumatic events is unclear. Here we use an animal model of predatory stress-induced anxiety-like behavior to investigate the role of the endocannabinoid system in the development of persistent anxiety states. Our main finding is that rats exposed to the fox pheromone 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a life-threatening stimulus for rodents, display a marked and selective increase in the mobilization of the endocannabinoid, 2-arachidonoyl-sn-glycerol (2-AG), in the amygdala. This effect lasts for at least 14 days after the stress has occurred. In addition, systemic or local pharmacological inhibition of monoacylglycerol lipase (MGL)—a lipid hydrolase that degrades 2-AG in presynaptic nerve terminals—elevates 2-AG levels and suppresses the anxiety-like behavior elicited by exposure to TMT. The results suggest that predator threat triggers long-term changes in 2-AG-mediated endocannabinoid signaling in the amygdala, and that pharmacological interventions targeting MGL might provide a therapeutic strategy for the treatment of chronic brain disorders initiated by trauma. PMID:26361059

  9. Effects of cannabinoid drugs on the reinforcing properties of food in gestationally undernourished rats.

    PubMed

    Wakley, Alexa A; Rasmussen, Erin B

    2009-11-01

    Involvement of the endocannabinoids in hyperphagia has been demonstrated, however, behavioral characterization of its role in food reinforcement is limited. The present study investigated whether 2-arachidonoyl glycerol, an endocannabinoid ligand, and rimonabant, a CB1 antagonist, change the reinforcing properties of food in gestationally undernourished rats (a putative model of obesity) vs controls. Albino dams were food deprived by 0 to 45% of their free-feeding weights up to day 18 of their gestational period. Their offspring were allowed to free-feed until postnatal day 75. Then, behavior of the offspring was placed under progressive ratio schedules of sucrose reinforcement. After baseline data were established, intraperitoneal injections of 2-AG (0.03-3.75 mg/kg), and rimonabant (SR141716, 0.3-3.0 mg/kg) were administered and compared across group. Results show gestationally undernourished (GU) rats as adults weighed less than controls at the time of testing and female offspring allowed to free-feed for over 35 weeks exhibited lower body weights than controls. Under baseline, GU rats had lower breakpoints than controls. 2-AG and rimonabant significantly increased and decreased, respectively, breakpoint and responses made per session, suggesting involvement of the cannabinoid system in food reinforcement. When comparing peak doses of 2-AG on breakpoint, gestationally undernourished rats exhibited lower peak doses than controls. These data suggest that under the gestation deprivation method employed, GU rats were thinner and had lower food reinforcer efficacy than controls, and may have heightened sensitivity to 2-AG.

  10. Yeast Aquaglyceroporins Use the Transmembrane Core to Restrict Glycerol Transport*

    PubMed Central

    Geijer, Cecilia; Ahmadpour, Doryaneh; Palmgren, Madelene; Filipsson, Caroline; Klein, Dagmara Medrala; Tamás, Markus J.; Hohmann, Stefan; Lindkvist-Petersson, Karin

    2012-01-01

    Aquaglyceroporins are transmembrane proteins belonging to the family of aquaporins, which facilitate the passage of specific uncharged solutes across membranes of cells. The yeast aquaglyceroporin Fps1 is important for osmoadaptation by regulating intracellular glycerol levels during changes in external osmolarity. Upon high osmolarity conditions, yeast accumulates glycerol by increased production of the osmolyte and by restricting glycerol efflux through Fps1. The extended cytosolic termini of Fps1 contain short domains that are important for regulating glycerol flux through the channel. Here we show that the transmembrane core of the protein plays an equally important role. The evidence is based on results from an intragenic suppressor mutation screen and domain swapping between the regulated variant of Fps1 from Saccharomyces cerevisiae and the hyperactive Fps1 ortholog from Ashbya gossypii. This suggests a novel mechanism for regulation of glycerol flux in yeast, where the termini alone are not sufficient to restrict Fps1 transport. We propose that glycerol flux through the channel is regulated by interplay between the transmembrane helices and the termini. This mechanism enables yeast cells to fine-tune intracellular glycerol levels at a wide range of extracellular osmolarities. PMID:22593571

  11. Glycerol Enhances the Antifungal Activity of Dairy Propionibacteria

    PubMed Central

    Lind, Helena; Broberg, Anders; Jacobsson, Karin; Jonsson, Hans; Schnürer, Johan

    2010-01-01

    Dairy propionibacteria are widely used in starter cultures for Swiss type cheese. These bacteria can ferment glucose, lactic acid, and glycerol into propionic acid, acetic acid, and carbon dioxide. This research examined the antifungal effect of dairy propionibacteria when glycerol was used as carbon source for bacterial growth. Five type strains of propionibacteria were tested against the yeast Rhodotorula mucilaginosa and the molds Penicillium commune and Penicillium roqueforti. The conversion of 13C glycerol by Propionibacterium jensenii was followed with nuclear magnetic resonance. In a dual culture assay, the degree of inhibition of the molds was strongly enhanced by an increase in glycerol concentrations, while the yeast was less affected. In broth cultures, decreased pH in glycerol medium was probably responsible for the complete inhibition of the indicator fungi. NMR spectra of the glycerol conversion confirmed that propionic acid was the dominant metabolite. Based on the results obtained, the increased antifungal effect seen by glycerol addition to cultures of propionibacteria is due to the production of propionic acid and pH reduction of the medium. PMID:21331381

  12. Optimizing aerobic conversion of glycerol to 3-hydroxypropionaldehyde.

    PubMed Central

    Slininger, P J; Bothast, R J

    1985-01-01

    When cells of Klebsiella pneumoniae NRRL B-199 (ATCC 8724) were grown aerobically on a rich glycerol medium and then suspended in buffer supplemented with semicarbazide and glycerol, aerobic conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA) ensued. Depending on conditions, 0.38 to 0.67 g of 3-HPA were formed per gram of glycerol consumed. This means that up to 83.8% of the carbon invested as glycerol could potentially be recovered as the target product, 3-HPA. Production of 3-HPA was sensitive to the age of cells harvested for resuspension and was nonexistent if cells were cultivated on glucose instead of glycerol as the sole carbon source. Compared with 24- and 72-h cells, 48-h cells produced 3-HPA at the highest rate and with the greatest yield. The cell biomass concentration present during the fermentation was never particularly critical to the 3-HPA yield, but initial fermentation rates and 3-HPA accumulation displayed a linear dependence on biomass concentration that faded when biomass exceeded 3 g/liter. Fermentation performance was a function of temperature, and an optimum initial specific 3-HPA productivity occurred at 32 degrees C, although the overall 3-HPA yield increased continuously within the 25 to 37 degrees C range studied. The pH optimum based on fermentation rate was different from that based on overall yield; 8 versus 7, respectively. Initial glycerol concentrations in the 20 to 50 g/liter range optimized initial 3-HPA productivity and yield. PMID:3911907

  13. Anaerobic glycerol production by Saccharomyces cerevisiae strains under hyperosmotic stress.

    PubMed

    Modig, Tobias; Granath, Katarina; Adler, Lennart; Lidén, Gunnar

    2007-05-01

    Glycerol formation is vital for reoxidation of nicotinamide adenine dinucleotide (reduced form; NADH) under anaerobic conditions and for the hyperosmotic stress response in the yeast Saccharomyces cerevisiae. However, relatively few studies have been made on hyperosmotic stress under anaerobic conditions. To study the combined effect of salt stress and anaerobic conditions, industrial and laboratory strains of S. cerevisiae were grown anaerobically on glucose in batch-cultures containing 40 g/l NaCl. The time needed for complete glucose conversion increased considerably, and the specific growth rates decreased by 80-90% when the cells were subjected to the hyperosmotic conditions. This was accompanied by an increased yield of glycerol and other by-products and reduced biomass yield in all strains. The slowest fermenting strain doubled its glycerol yield (from 0.072 to 0.148 g/g glucose) and a nearly fivefold increase in acetate formation was seen. In more tolerant strains, a lower increase was seen in the glycerol and in the acetate, succinate and pyruvate yields. Additionally, the NADH-producing pathway from acetaldehyde to acetate was analysed by overexpressing the stress-induced gene ALD3. However, this had no or very marginal effect on the acetate and glycerol yields. In the control experiments, the production of NADH from known sources well matched the glycerol formation. This was not the case for the salt stress experiments in which the production of NADH from known sources was insufficient to explain the formed glycerol.

  14. Glycerol metabolism and bitterness producing lactic acid bacteria in cidermaking.

    PubMed

    Garai-Ibabe, G; Ibarburu, I; Berregi, I; Claisse, O; Lonvaud-Funel, A; Irastorza, A; Dueñas, M T

    2008-02-10

    Several lactic acid bacteria were isolated from bitter tasting ciders in which glycerol was partially removed. The degradation of glycerol via glycerol dehydratase pathway was found in 22 out of 67 isolates. The confirmation of glycerol degradation by this pathway was twofold: showing their glycerol dehydratase activity and detecting the presence of the corresponding gene by a PCR method. 1,3-propanediol (1,3-PDL) and 3-hydroxypropionic acid (3-HP) were the metabolic end-products of glycerol utilization, and the accumulation of the acrolein precursor 3-hydroxypropionaldehyde (3-HPA) was also detected in most of them. The strain identification by PCR-DGGE rpoB showed that Lactobacillus collinoides was the predominant species and only 2 belonged to Lactobacillus diolivorans. Environmental conditions conducting to 3-HPA accumulation in cidermaking were studied by varying the fructose concentration, pH and incubation temperature in L. collinoides 17. This strain failed to grow with glycerol as sole carbon source and the addition of fructose enhanced both growth and glycerol degradation. Regarding end-products of glycerol metabolism, 1,3-PDL was always the main end-product in all environmental conditions assayed, the only exception being the culture with 5.55 mM fructose, where equimolar amounts of 1,3-PDL and 3-HP were found. The 3-HPA was transitorily accumulated in the culture medium under almost all culture conditions, the degradation rate being notably slower at 15 degrees C. However, no disappearance of 3-HPA was found at pH 3.6, a usual value in cider making. After sugar exhaustion, L. collinoides 17 oxidated lactic acid and/or mannitol to obtain energy and these oxidations were accompanied by the removal of the toxic 3-HPA increasing the 1,3-PDL, 3-HP and acetic acid contents.

  15. Accelerated glycerol fermentation in Escherichia coli using methanogenic formate consumption.

    PubMed

    Richter, Katrin; Gescher, Johannes

    2014-06-01

    Escherichia coli can ferment glycerol anaerobically only under very defined restrictive conditions. Hence, it was the aim of this study to overcome this limitation via a co-cultivation approach. Anaerobic glycerol fermentation by a pure E. coli culture was compared to a co-culture that also contained the formate-oxidizing methanogen Methanobacterium formicicum. Co-cultivation of the two strains led to a more than 11-fold increased glycerol consumption. Furthermore, it supported a constantly neutral pH and a shift from ethanol to succinate production. Moreover, M. formicicum was analyzed for its ability to grow on different standard media and a surprising versatility could be demonstrated.

  16. Glycerol Dehydrogenase Plays a Dual Role in Glycerol Metabolism and 2,3-Butanediol Formation in Klebsiella pneumoniae *

    PubMed Central

    Wang, Yu; Tao, Fei; Xu, Ping

    2014-01-01

    Glycerol dehydrogenase (GDH) is an important polyol dehydrogenase for glycerol metabolism in diverse microorganisms and for value-added utilization of glycerol in the industry. Two GDHs from Klebsiella pneumoniae, DhaD and GldA, were expressed in Escherichia coli, purified and characterized for substrate specificity and kinetic parameters. Both DhaD and GldA could catalyze the interconversion of (3R)-acetoin/(2R,3R)-2,3-butanediol or (3S)-acetoin/meso-2,3-butanediol, in addition to glycerol oxidation. Although purified GldA appeared more active than DhaD, in vivo inactivation and quantitation of their respective mRNAs indicate that dhaD is highly induced by glycerol and plays a dual role in glycerol metabolism and 2,3-butanediol formation. Complementation in K. pneumoniae further confirmed the dual role of DhaD. Promiscuity of DhaD may have vital physiological consequences for K. pneumoniae growing on glycerol, which include balancing the intracellular NADH/NAD+ ratio, preventing acidification, and storing carbon and energy. According to the kinetic response of DhaD to modified NADH concentrations, DhaD appears to show positive homotropic interaction with NADH, suggesting that the physiological role could be regulated by intracellular NADH levels. The co-existence of two functional GDH enzymes might be due to a gene duplication event. We propose that whereas DhaD is specialized for glycerol utilization, GldA plays a role in backup compensation and can turn into a more proficient catalyst to promote a survival advantage to the organism. Revelation of the dual role of DhaD could further the understanding of mechanisms responsible for enzyme evolution through promiscuity, and guide metabolic engineering methods of glycerol metabolism. PMID:24429283

  17. Production of polyhydroxybutyrate and alginate from glycerol by Azotobacter vinelandii under nitrogen-free conditions.

    PubMed

    Yoneyama, Fuminori; Yamamoto, Mayumi; Hashimoto, Wataru; Murata, Kousaku

    2015-01-01

    Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-d-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including γ-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source.

  18. Production of polyhydroxybutyrate and alginate from glycerol by Azotobacter vinelandii under nitrogen-free conditions

    PubMed Central

    Yoneyama, Fuminori; Yamamoto, Mayumi; Hashimoto, Wataru; Murata, Kousaku

    2015-01-01

    Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-d-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including γ-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source. PMID:25880041

  19. Glycerol administration before endurance exercise: metabolism, urinary glycerol excretion and effects on doping-relevant blood parameters.

    PubMed

    Koehler, Karsten; Braun, Hans; de Marees, Markus; Geyer, Hans; Thevis, Mario; Mester, Joachim; Schaenzer, Wilhelm

    2014-03-01

    Glycerol is prohibited as a masking agent by the World Anti-Doping Agency and a urinary threshold has recently been recommended. However, little is known about urinary glycerol excretion after exercise, when (1) exogenous glycerol is metabolized increasingly and (2) endogenous glycerol levels are elevated. The purpose of the placebo-controlled cross-over study was to determine the effects of pre-exercise glycerol administration on glycerol metabolism, urinary excretion, and selected blood parameters. After administration of glycerol (G; 1.0 g/kg body weight (BW) + 25 ml fluid/kg BW) or placebo (P; 25 ml fluid/kg), 14 cyclists exercised 90 min at 60% VO2max . Samples were taken at 0 h (before administration), 2.5 h (before exercise), 4 h (after exercise) and 6.5 h and additional urine samples were collected until 24 h. Exercise increased endogenous plasma glycerol (0.51 ± 0.21 mmol/l) but peak concentrations were much higher in G (2.5 h: 15.6 ± 7.8 mmol/l). Urinary glycerol increased rapidly (58,428 ± 71,084 µg/ml after 2.5 h) and was significantly higher than in P until 13.6 ± 0.9 h (p < 0.01). In comparison with placebo administration, G caused significantly greater changes in plasma volume and haemoglobin concentrations after 2.5 h. BW and urine production were significantly different between P and G after 2.5 h and post-exercise. Despite exercise-induced increases in endogenous glycerol in the control group, urinary excretion remained well below the previously recommended threshold. In addition, exercise-related glycerol degradation did not appear to negatively affect the detection of exogenously administered glycerol.

  20. Comprehensive utilization of glycerol from sugarcane bagasse pretreatment to fermentation.

    PubMed

    Jiang, Liqun; Zheng, Anqing; Zhao, Zengli; He, Fang; Li, Haibin

    2015-11-01

    In this study, the effects of glycerol pretreatment on subsequent glycerol fermentation and biomass fast pyrolysis were investigated. The liquid fraction from the pretreatment process was evaluated to be feasible for fermentation by Paenibacillus polymyxa and could be an economic substrate. The pretreated biomass was further utilized to obtain levoglucosan by fast pyrolysis. The pretreated sugarcane bagasse exhibited significantly higher levoglucosan yield (47.70%) than that of un-pretreated sample (11.25%). The promotion could likely be attributed to the effective removal of alkali and alkaline earth metals by glycerol pretreatment. This research developed an economically viable manufacturing paradigm to utilize glycerol comprehensively and enhance the formation of levoglucosan effectively from lignocellulose.

  1. Physicochemical characterization of oil palm mesocarp fibre treated with glycerol

    NASA Astrophysics Data System (ADS)

    Nor Hamizah M., A.; Roila, A.; Rahimi M., Y.

    2015-09-01

    Lignocellulose has been identified as another source for conversion into value added products. In the present work, physicochemical features from the oil palm mesocarp fibre treated by using pure glycerol with 2% (w/w) NaOH catalyst and crude glycerol have been studied. Treatment was conducted at temperatures 150 °C for 60 min. Fibre treated by crude glycerol resulted in high percentages of holocellulose and lower content of insoluble lignin. These results suggest that crude glycerol can be used as an alternative solvent for pretreatment process. The characterization treated fibre by means of FTIR and TGA has shown significant differences compared to untreated fibre. It was revealed that treated fibre successful eliminated hemicellulose and reduce of lignin content.

  2. Glycerol extracting dealcoholization for the biodiesel separation process.

    PubMed

    Ye, Jianchu; Sha, Yong; Zhang, Yun; Yuan, Yunlong; Wu, Housheng

    2011-04-01

    By means of utilizing sunflower oil and Jatropha oil as raw oil respectively, the biodiesel transesterification production and the multi-stage extracting separation were carried out experimentally. Results indicate that dealcoholized crude glycerol can be utilized as the extracting agent to achieve effective separation of methanol from the methyl ester phase, and the glycerol content in the dealcoholized methyl esters is as low as 0.02 wt.%. For the biodiesel separation process utilizing glycerol extracting dealcoholization, its technical and equipment information were acquired through the rigorous process simulation in contrast to the traditional biodiesel distillation separation process, and results show that its energy consumption decrease about 35% in contrast to that of the distillation separation process. The glycerol extracting dealcoholization has sufficient feasibility and superiority for the biodiesel separation process.

  3. Vibrational properties of bioprotectant mixtures of trehalose and glycerol.

    PubMed

    Magazù, Salvatore; Migliardo, Federica; Parker, Stewart F

    2011-09-22

    In this work vibrational spectra of mixtures of two glass-forming bioprotectant systems, i.e., trehalose and glycerol, are collected at very low temperature by using the indirect geometry time-of-flight (t.o.f.) TOSCA spectrometer at the ISIS Pulse Neutron Facility (Rutherford Appleton Laboratory, Oxford, U.K.). The main aim of this work is to investigate, through inelastic neutron scattering (INS), the vibrational behavior of trehalose and its mixtures with glycerol at different concentration values in order to characterize the changes induced by glycerol on the trehalose hydrogen bonded network. The obtained experimental findings, which are discussed and interpreted in the framework of previous INS, quasi elastic neutron scattering (QENS) and molecular simulation data obtained on trehalose/glycerol mixtures at different concentration and temperature values, will be linked to the different mixtures bioprotectant effectiveness.

  4. Energetics of glycerol conduction through aquaglyceroporin GlpF

    NASA Astrophysics Data System (ADS)

    Jensen, Morten Ø.; Park, Sanghyun; Tajkhorshid, Emad; Schulten, Klaus

    2002-05-01

    Aquaglyceroporin GlpF selectively conducts water and linear polyalcohols, such as glycerol, across the inner membrane of Escherichia coli. We report steered molecular dynamics simulations of glycerol conduction through GlpF, in which external forces accelerate the transchannel conduction in a manner that preserves the intrinsic conduction mechanism. The simulations reveal channel-glycerol hydrogen bonding interactions and the stereoselectivity of the channel. Employing Jarzynski's identity between free energy and irreversible work, we reconstruct the potential of mean force along the conduction pathway through a time series analysis of molecular dynamics trajectories. This potential locates binding sites and barriers inside the channel; it also reveals a low energy periplasmic vestibule suited for efficient uptake of glycerol from the environment.

  5. Renewable hydrogen and carbon nanotubes from biodiesel waste glycerol.

    PubMed

    Wu, Chunfei; Wang, Zichun; Williams, Paul T; Huang, Jun

    2013-09-25

    In this report, we introduce a novel and commercially viable method to recover renewable hydrogen and carbon nanotubes from waste glycerol produced in the biodiesel process. Gas-phase catalytic reforming converts glycerol to clean hydrogen fuel and by replacing the problematical coke formed on the catalyst with high value carbon nanotubes, added value can be realised. Additional benefits of around 2.8 kg CNTs from the reforming of 1 tonne of glycerol and the production of 500 Nm(3) H2 could have a considerable impact on the economics of glycerol utilization. Thereby, the contribution of this research will be a significant step forward in solving a current major technical and economic challenge faced by the biofuels industry.

  6. Recent Advances in Glycerol Polymers: Chemistry and Biomedical Applications

    PubMed Central

    Zhang, Heng

    2015-01-01

    Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, we describe the underlying chemistry of glycerol, which provides access to a range of monomers for subsequent polymerizations. We then review the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth. Next, we describe several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity. Fourth, we describe the growing market opportunity for the use of polymers in medicine. Finally we conclude and summarize the findings, as well as discuss potential opportunities for continued research efforts. PMID:25308354

  7. Renewable hydrogen and carbon nanotubes from biodiesel waste glycerol

    PubMed Central

    Wu, Chunfei; Wang, Zichun; Williams, Paul T.; Huang, Jun

    2013-01-01

    In this report, we introduce a novel and commercially viable method to recover renewable hydrogen and carbon nanotubes from waste glycerol produced in the biodiesel process. Gas-phase catalytic reforming converts glycerol to clean hydrogen fuel and by replacing the problematical coke formed on the catalyst with high value carbon nanotubes, added value can be realised. Additional benefits of around 2.8 kg CNTs from the reforming of 1 tonne of glycerol and the production of 500 Nm3 H2 could have a considerable impact on the economics of glycerol utilization. Thereby, the contribution of this research will be a significant step forward in solving a current major technical and economic challenge faced by the biofuels industry. PMID:24067754

  8. Recent advances in glycerol polymers: chemistry and biomedical applications.

    PubMed

    Zhang, Heng; Grinstaff, Mark W

    2014-11-01

    Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, the underlying chemistry of glycerol that provides access to a range of monomers for subsequent polymerizations is described. Then, the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth are reviewed. Next, several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity are described. Fourth, the growing market opportunity for the use of polymers in medicine is described. Finally, the findings are concluded and summarized, as well as the potential opportunities for continued research efforts are discussed.

  9. Optimizing aerobic conversion of glycerol to 3-hydroxypropionaldehyde

    SciTech Connect

    Slininger, P.J.; Bothast, R.J.

    1985-12-01

    Chemical oxidation of 3-hydroxypropionaldehyde (3-HPA) leads to acrylic acid, an industrially important polymerizable monomer currently derived from petroleum. As the availability of petroleum declines, 3-HPA may become attractive as a product to be obtained through fermentation of glycerol, a renewable resource. When cells of Klebsiella pneumoniae NRRL B-199 (ATCC 8724) were grown aerobically on a rich glycerol medium and then suspended in buffer supplemented with semicarbazide and glycerol, aerobic conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA) ensued. Depending on conditions, 0.38 to 0.67 g of 3-HPA were formed per gram of glycerol consumed. This means that up to 83.8% of the carbon invested as glycerol could potentially be recovered as the target product, 3-HPA. Production of 3-HPA was sensitive to the age of cells harvested for resuspension and was nonexistent if cells were cultivated on glucose instead of glycerol as the sole carbon source. Compared with 24- and 72-h cells, 48-h cells produced 3-HPA at the highest rate and with the greatest yield. The cell biomass concentration present during the fermentation was never particularly critical to the 3-HPA yield, but initial fermentation rates and 3-HPA accumulation displayed a linear dependence on biomass concentration that faded when biomass exceeded 3 g/liter. Fermentation performance was a function of temperature, and an optimum initial specific 3-HPA productivity occurred at 32/sup 0/C, although the overall 3-HPA yield increased continuously within the 25 to 37/sup 0/C range studied. The pH optimum based on fermentation rate was different from that based on overall yield; 8 versus 7, respectively. Initial glycerol concentrations in the 20 to 50 g/liter range optimized initial 3-HPA productivity and yield.

  10. Quantitative NMR Analysis of Partially Substituted Biodiesel Glycerols

    SciTech Connect

    Nagy, M.; Alleman, T. L.; Dyer, T.; Ragauskas, A. J.

    2009-01-01

    Phosphitylation of hydroxyl groups in biodiesel samples with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane followed by 31P-NMR analysis provides a rapid quantitative analytical technique for the determination of substitution patterns on partially esterified glycerols. The unique 31P-NMR chemical shift data was established with a series mono and di-substituted fatty acid esters of glycerol and then utilized to characterize an industrial sample of partially processed biodiesel.

  11. Comparative study of muscle regeneration following cardiotoxin and glycerol injury.

    PubMed

    Mahdy, Mohamed A A; Lei, Hsiao Yin; Wakamatsu, Jun-Ichi; Hosaka, Yoshinao Z; Nishimura, Takanori

    2015-11-01

    In the present study, we examined muscle regeneration following two types of chemical injuries, cardiotoxin (CTX) and glycerol, in order to compare their effect on the morphological characteristics during muscle regeneration, in addition we studied the structural changes of the intramuscular connective tissue (IMCT) during the regeneration process, by scanning electron microscopy (SEM) after digestion of the cellular elements of the muscle with sodium hydroxide. Tibialis anterior (TA) muscles of adult male mice were injected either with CTX or glycerol. Muscle degeneration was greater in the CTX-injured model than in the glycerol-injured model at day 4 post injection. Muscle regeneration started at day 7 in both the CTX and glycerol models. However, the CTX-injured model showed a higher myotube density and larger myotube diameter than the glycerol-injured model at days 10 and 14 post injection. On other hand, adipocyte infiltration was detected in the glycerol-injured model. In contrast, no adipocytes could be detected in the CTX-injured model. Furthermore, ultrastructural analysis showed a significant difference in myofiber damage and regeneration between the two models. SEM of the IMCT showed a transient increase in endomysial collagen deposition at early stages of regeneration in the CTX-injured model. In contrast, glycerol-injured model showed slight endomysial collagen deposition. Our results suggest that changes in IMCT affect the efficiency of muscle regeneration. Studying the three dimensional structure of IMCT may help clinical therapies to reduce skeletal muscle fibrosis. To our knowledge this is the first time the changes in IMCT following CTX and glycerol injury using SEM-cell maceration technique have been compared.

  12. Glycerol accumulation in edema formation following diffuse traumatic brain injury.

    PubMed

    Ali, Ahmer; Konakondla, Sanjay; Zwagerman, Nathan T; Peng, Changya; Schafer, Steven; Ding, Jamie Y; Dornbos, David; Sikharam, Chaitanya; Geng, Xiaokun; Guthikonda, Murali; Kreipke, Christian W; Rafols, José A; Ding, Yuchuan

    2012-06-01

    Traumatic brain injury (TBI) induces brain edema via water and glycerol transport channels, called aquaporins (AQPs). The passage of glycerol across brain cellular compartments has been shown during edema. Using a modified impact/head acceleration rodent model of diffuse TBI, we assessed the role of hypoxia inducible factor (HIF)-1alpha in regulating AQP9 expression and glycerol accumulation during the edema formation. Adult (400-425 g) male Sprague-Dawley rats received a closed head injury with a weight drop (450 g, 2-m height) and were allowed to survive up to 48 hours. Some rat groups were administered 2-methoxyestradiol (2ME2, a HIF-1alpha inhibitor) 30 minutes after injury and were euthanized at 4 and 24 hours after injury. Brain edema was measured directly by water content, and glycerol concentration was determined by the Cayman Glycerol Assay. HIF-1alpha and AQP9 protein levels were assessed by Western immunoblotting. This study demonstrated a significant (P<0·05) increase in brain water content at 4-48 hours following impact. Cerebral glycerol was significantly (P<0.05) up-regulated at as early as 1 hour and remained at high levels for up to 48 hours. Similarly, significant (P<0.05) increases in HIF-1alpha and AQP9 protein levels were found at 1 hour and up to 48 hours after injury. Compared to untreated but injured rats, inhibition of HIF-1alpha by 2ME2 significantly (P<0.05) reduced the TBI-induced AQP9 up-regulation. This reduction was temporally associated with significant (P<0.05) decreases in both edema and glycerol accumulation. The data suggested an associated induction of HIF-1alpha, AQP9, and extracellular glycerol accumulation in edema formation following diffuse TBI. The implication of HIF-1alpha and AQP9 underlying TBI-induced edema formation offers possibilities for novel TBI therapies.

  13. A comparison of absorption of glycerol tristearate and glycerol trioleate by rat small intestine

    SciTech Connect

    Bergstedt, S.E.; Hayashi, H.; Kritchevsky, D.; Tso, P. )

    1990-09-01

    Generally, fats rich in saturated fatty acids raise serum cholesterol, whereas fats rich in polyunsaturated fatty acids lower it. There appear to be exceptions; e.g., stearic acid (18:0)-rich fats have little or no effect on serum cholesterol concentrations. This apparent lack of cholesterolemic effect of stearic acid-rich fat could be because intestinal absorption of fat is poor or subsequent plasma and/or tissue metabolism of fat is different. To investigate mechanisms involved, we compared intestinal digestion, uptake, and lymphatic transport of glycerol tristearate (TS) and glycerol trioleate (TO, 18:1). Two groups of rats bearing intestinal lymph fistulas were used. TO rats were fed intraduodenally for 8 h at a constant rate a lipid emulsion of 25 mumols/h of TO (labeled with glycerol tri(9,10 (n)-3H)oleate), 7.8 mumols of egg phosphatidylcholine, and 57 mumols of sodium taurocholate in 3 ml of phosphate-buffered saline. TS rats were fed the same lipid emulsion except that TS replaced TO and the emulsion was labeled with glyceryl (1,3-14C)tristearate. The lymph triglyceride and radioactivity were determined. After infusion, the luminal and mucosal radioactive lipid content was analyzed. The results showed that there was significantly less lipid transported in the lymph of TS rats compared with TO rats. The results also showed a significant decrease in the absorption of TS as compared with TO. This was due in part to poor lipolysis. In addition, the lipid absorbed by the intestine of the TS rats was transported into lymph less efficiently than in TO rats.

  14. Degradation behavior of poly(glycerol sebacate).

    PubMed

    Pomerantseva, Irina; Krebs, Nicholas; Hart, Alison; Neville, Craig M; Huang, Albert Y; Sundback, Cathryn A

    2009-12-15

    Poly(glycerol sebacate) (PGS), a promising scaffold material for soft tissue engineering applications, is a soft, tough elastomer with excellent biocompatibility. However, the rapid in vivo degradation rate of PGS limits its use as a scaffold material. To determine the impact of crosslink density on degradation rate, a family of PGS materials was synthesized by incrementally increasing the curing time from 42 to 144 h, at 120 degrees C and 10 mTorr vacuum. As expected, PGS became a stiffer, tougher, and stronger elastomer with increasing curing time. PGS disks were subcutaneously implanted into rats and periodically harvested; only mild tissue responses were observed and the biocompatibility remained excellent. Regardless of crosslink density, surface erosion degradation was observed. The sample dimensions linearly decreased with implantation time, and the mass loss rates were constant after 1-week implantation. As surface erosion degradation frequently correlates with enzymatic digestion, parallel in vitro digestion studies were conducted in lipase solutions which hydrolyze ester bonds. Enzymatic digestion played a significant role in degrading PGS, and the mass loss rates were not a function of curing time. Alternative chemistry approaches will be required to decrease the enzymatic hydrolysis rate of the ester bonds in PGS polymers.

  15. Value-added uses for crude glycerol--a byproduct of biodiesel production

    PubMed Central

    2012-01-01

    Biodiesel is a promising alternative, and renewable, fuel. As its production increases, so does production of the principle co-product, crude glycerol. The effective utilization of crude glycerol will contribute to the viability of biodiesel. In this review, composition and quality factors of crude glycerol are discussed. The value-added utilization opportunities of crude glycerol are reviewed. The majority of crude glycerol is used as feedstock for production of other value-added chemicals, followed by animal feeds. PMID:22413907

  16. Control of mechanical properties of chitin nanofiber film using glycerol without losing its characteristics.

    PubMed

    Ifuku, Shinsuke; Ikuta, Akiko; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki

    2014-01-30

    Surface-deacetylated chitin nanofiber films plasticized with glycerol were prepared to control mechanical properties. Nanofiber networks were able to retain excessive glycerol content up to 70% to obtain self-standing film. All films were flexible and highly transparent independent of glycerol content. Glycerol significantly decreased the Young's moduli and tensile strengths, and increased the fracture strain due to its plasticizing effect. At the same time, glycerol did not change the high transparency or the low thermal expansion of the nanofiber film.

  17. Processes and systems for the production of propylene glycol from glycerol

    SciTech Connect

    Frye, John G; Oberg, Aaron A; Zacher, Alan H

    2015-01-20

    Processes and systems for converting glycerol to propylene glycol are disclosed. The glycerol feed is diluted with propylene glycol as the primary solvent, rather than water which is typically used. The diluted glycerol feed is sent to a reactor where the glycerol is converted to propylene glycol (as well as other byproducts) in the presence of a catalyst. The propylene glycol-containing product from the reactor is recycled as a solvent for the glycerol feed.

  18. Sugar-glycerol cofermentations in lactobacilli: the fate of lactate.

    PubMed

    Veiga da Cunha, M; Foster, M A

    1992-02-01

    The simultaneous fermentation of glycerol and sugar by lactobacillus brevis B22 and Lactobacillus buchneri B190 increases both the growth rate and total growth. The reduction of glycerol to 1,3-propanediol by the lactobacilli was found to influence the metabolism of the sugar cofermented by channelling some of the intermediate metabolites (e.g., pyruvate) towards NADH-producing (rather than NADH-consuming) reactions. Ultimately, the absolute requirement for NADH to prevent the accumulation of 3-hydroxypropionaldehyde leads to a novel lactate-glycerol cofermentation. As a result, additional ATP can be made not only by (i) converting pyruvate to acetate via acetyl phosphate rather than to the ethanol usually found and (ii) oxidizing part of the intermediate pyruvate to acetate instead of the usual reduction to lactate but also by (iii) reoxidation of accumulated lactate to acetate via pyruvate. The conversion of lactate to pyruvate is probably catalyzed by NAD-independent lactate dehydrogenases that are found only in the cultures oxidizing lactate and producing 1,3-propanediol, suggesting a correlation between the expression of these enzymes and a raised intracellular NAD/NADH ratio. The enzymes metabolizing glycerol (glycerol dehydratase and 1,3-propanediol dehydrogenase) were expressed in concert without necessary induction by added glycerol, although their expression may also be influenced by the intracellular NAD/NADH ratio set by the different carbohydrates fermented.

  19. Glycerol fermentation by (open) mixed cultures: a chemostat study.

    PubMed

    Temudo, Margarida F; Poldermans, Rolf; Kleerebezem, Robbert; van Loosdrecht, Mark C M

    2008-08-15

    Glycerol is an important byproduct of bioethanol and biodiesel production processes. This study aims to evaluate its potential application in mixed culture fermentation processes to produce bulk chemicals. Two chemostat reactors were operated in parallel, one fed with glycerol and the other with glucose. Both reactors operated at a pH of 8 and a dilution rate of 0.1 h(-1). Glycerol was mainly converted into ethanol and formate. When operated under substrate limiting conditions, 60% of the substrate carbon was converted into ethanol and formate in a 1:1 ratio. This product spectrum showed sensitivity to the substrate concentration, which partly shifted towards 1,3-propanediol and acetate in a 2:1 ratio at increasing substrate concentrations. Glucose fermentation mainly generated acetate, ethanol and butyrate. At higher substrate concentrations, acetate and ethanol were the dominant products. Co-fermentations of glucose-glycerol were performed with both mixed cultures, previously cultivated on glucose and on glycerol. The product spectrum of the two experiments was very similar: the main products were ethanol and butyrate (38% and 34% of the COD converted, respectively). The product spectrum obtained for glucose and glycerol fermentation could be explained based on the general metabolic pathways found for fermentative microorganisms and on the metabolic constraints: maximization of the ATP production rate and balancing the reducing equivalents involved.

  20. Microaerobic conversion of glycerol to ethanol in Escherichia coli.

    PubMed

    Wong, Matthew S; Li, Mai; Black, Ryan W; Le, Thao Q; Puthli, Sharon; Campbell, Paul; Monticello, Daniel J

    2014-05-01

    Glycerol has become a desirable feedstock for the production of fuels and chemicals due to its availability and low price, but many barriers to commercialization remain. Previous investigators have made significant improvements in the yield of ethanol from glycerol. We have developed a fermentation process for the efficient microaerobic conversion of glycerol to ethanol by Escherichia coli that presents solutions to several other barriers to commercialization: rate, titer, specific productivity, use of inducers, use of antibiotics, and safety. To increase the rate, titer, and specific productivity to commercially relevant levels, we constructed a plasmid that overexpressed glycerol uptake genes dhaKLM, gldA, and glpK, as well as the ethanol pathway gene adhE. To eliminate the cost of inducers and antibiotics from the fermentation, we used the adhE and icd promoters from E. coli in our plasmid, and we implemented glycerol addiction to retain the plasmid. To address the safety issue of off-gas flammability, we optimized the fermentation process with reduced-oxygen sparge gas to ensure that the off-gas remained nonflammable. These advances represent significant progress toward the commercialization of an E. coli-based glycerol-to-ethanol process.

  1. Microaerobic Conversion of Glycerol to Ethanol in Escherichia coli

    PubMed Central

    Wong, Matthew S.; Li, Mai; Black, Ryan W.; Le, Thao Q.; Puthli, Sharon; Campbell, Paul

    2014-01-01

    Glycerol has become a desirable feedstock for the production of fuels and chemicals due to its availability and low price, but many barriers to commercialization remain. Previous investigators have made significant improvements in the yield of ethanol from glycerol. We have developed a fermentation process for the efficient microaerobic conversion of glycerol to ethanol by Escherichia coli that presents solutions to several other barriers to commercialization: rate, titer, specific productivity, use of inducers, use of antibiotics, and safety. To increase the rate, titer, and specific productivity to commercially relevant levels, we constructed a plasmid that overexpressed glycerol uptake genes dhaKLM, gldA, and glpK, as well as the ethanol pathway gene adhE. To eliminate the cost of inducers and antibiotics from the fermentation, we used the adhE and icd promoters from E. coli in our plasmid, and we implemented glycerol addiction to retain the plasmid. To address the safety issue of off-gas flammability, we optimized the fermentation process with reduced-oxygen sparge gas to ensure that the off-gas remained nonflammable. These advances represent significant progress toward the commercialization of an E. coli-based glycerol-to-ethanol process. PMID:24584248

  2. Key enzymes catalyzing glycerol to 1,3-propanediol.

    PubMed

    Jiang, Wei; Wang, Shizhen; Wang, Yuanpeng; Fang, Baishan

    2016-01-01

    Biodiesel can replace petroleum diesel as it is produced from animal fats and vegetable oils, and it produces about 10 % (w/w) glycerol, which is a promising new industrial microbial carbon, as a major by-product. One of the most potential applications of glycerol is its biotransformation to high value chemicals such as 1,3-propanediol (1,3-PD), dihydroxyacetone (DHA), succinic acid, etc., through microbial fermentation. Glycerol dehydratase, 1,3-propanediol dehydrogenase (1,3-propanediol-oxydoreductase), and glycerol dehydrogenase, which were encoded, respectively, by dhaB, dhaT, and dhaD and with DHA kinase are encompassed by the dha regulon, are the three key enzymes in glycerol bioconversion into 1,3-PD and DHA, and these are discussed in this review article. The summary of the main research direction of these three key enzyme and methods of glycerol bioconversion into 1,3-PD and DHA indicates their potential application in future enzymatic research and industrial production, especially in biodiesel industry.

  3. Controlled synthesis and photocatalysis of sea urchin-like Fe3O4@TiO2@Ag nanocomposites

    NASA Astrophysics Data System (ADS)

    Zhao, Yilin; Tao, Chengran; Xiao, Gang; Wei, Guipeng; Li, Linghui; Liu, Changxia; Su, Haijia

    2016-02-01

    Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the core and nanofiber TiO2/Fe3O4/Ag nanoheterojunctions as the shell; and Ag nanoparticles with diameter of approximately 4 nm are loaded both on TiO2 nanofibers and inside the cavities of sea urchin-like Fe3O4@TiO2 nanocomposites uniformly. Ag nanoparticles lead to the production of more photogenerated charges in the TiO2/Fe3O4/Ag heterojunction via LSPR absorption, and enhance the band-gap absorption of TiO2, while the Fe3O4 cocatalyst provides the active sites for oxygen reduction by the effective transfer of photogenerated electrons to oxygen. So the photocatalytic performance is improved due to the synergistic effect of TiO2/Fe3O4/Ag nanoheterojunctions. As photocatalysts under UV and visible irradiation, the as-synthesized nanocomposites display enhanced photocatalytic and recycling properties for the degradation of ampicillin. Moreover, they present better broad-spectrum antibiosis under visible irradiation. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, makes this multifunctional nanostructure a promising candidate for antibiosis and remediation in aquatic environmental contamination in the future.Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the

  4. Effect of Indium Content on the Melting Point, Dross, and Oxidation Characteristics of Sn-2Ag-3Bi-xIn Solders.

    PubMed

    Jeon, Ae-Jeong; Kim, Seong-Jun; Lee, Sang-Hoon; Kang, Chung-Yun

    2013-06-01

    This paper presents the effect of indium (In) content on the melting temperature, wettabililty, dross formation, and oxidation characteristics of the Sn-2Ag-3Bi-xIn alloy. The melting temperature of the Sn-2Ag-3Bi-xIn alloy (2 ≤ x ≤ 6) was lower than 473 K. The melting range between the solidus and liquidus temperatures was approximately 20 K, irrespective of the indium content. As the indium content increased, the wetting time increased slightly and the maximum wetting force remained to be mostly constant. The dross formation decreased to approximately 50% when adding 1In to Sn-2Ag-3Bi, and no dross formation was observed in the case of Sn-2Ag-3Bi-xIn alloy (x ≥ 1.5) at 523 K for 180 min. Upon approaching the inside of the oxidized solder of the Sn-2Ag-3Bi-1.5In alloy from the surface, the O and In contents decreased and the Sn content increased based on depth profiling analysis using Auger electron spectroscopy (AES). The mechanism for restraining dross (Sn oxidation) of Sn-2Ag-3Bi alloy with addition of indium may be due to surface segregation of indium. This is due to the lower formation energy of indium oxide than those of Sn oxidation.

  5. Controlled synthesis and photocatalysis of sea urchin-like Fe3O4@TiO2@Ag nanocomposites.

    PubMed

    Zhao, Yilin; Tao, Chengran; Xiao, Gang; Wei, Guipeng; Li, Linghui; Liu, Changxia; Su, Haijia

    2016-03-07

    Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the core and nanofiber TiO2/Fe3O4/Ag nanoheterojunctions as the shell; and Ag nanoparticles with diameter of approximately 4 nm are loaded both on TiO2 nanofibers and inside the cavities of sea urchin-like Fe3O4@TiO2 nanocomposites uniformly. Ag nanoparticles lead to the production of more photogenerated charges in the TiO2/Fe3O4/Ag heterojunction via LSPR absorption, and enhance the band-gap absorption of TiO2, while the Fe3O4 cocatalyst provides the active sites for oxygen reduction by the effective transfer of photogenerated electrons to oxygen. So the photocatalytic performance is improved due to the synergistic effect of TiO2/Fe3O4/Ag nanoheterojunctions. As photocatalysts under UV and visible irradiation, the as-synthesized nanocomposites display enhanced photocatalytic and recycling properties for the degradation of ampicillin. Moreover, they present better broad-spectrum antibiosis under visible irradiation. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, makes this multifunctional nanostructure a promising candidate for antibiosis and remediation in aquatic environmental contamination in the future.

  6. Modulation of the Endocannabinoids N-Arachidonoylethanolamine (AEA) and 2-Arachidonoylglycerol (2-AG) on Executive Functions in Humans

    PubMed Central

    Fagundo, Ana B.; de la Torre, Rafael; Jiménez-Murcia, Susana; Agüera, Zaida; Pastor, Antoni; Casanueva, Felipe F.; Granero, Roser; Baños, Rosa; Botella, Cristina; del Pino-Gutierrez, Amparo; Fernández-Real, Jose M.; Fernández-García, Jose C.; Frühbeck, Gema; Gómez-Ambrosi, Javier; Menchón, José M.; Moragrega, Inés; Rodríguez, Roser; Tárrega, Salomé; Tinahones, Francisco J.; Fernández-Aranda, Fernando

    2013-01-01

    Animal studies point to an implication of the endocannabinoid system on executive functions. In humans, several studies have suggested an association between acute or chronic use of exogenous cannabinoids (Δ9-tetrahydrocannabinol) and executive impairments. However, to date, no published reports establish the relationship between endocannabinoids, as biomarkers of the cannabinoid neurotransmission system, and executive functioning in humans. The aim of the present study was to explore the association between circulating levels of plasma endocannabinoids N-arachidonoylethanolamine (AEA) and 2-Arachidonoylglycerol (2-AG) and executive functions (decision making, response inhibition and cognitive flexibility) in healthy subjects. One hundred and fifty seven subjects were included and assessed with the Wisconsin Card Sorting Test; Stroop Color and Word Test; and Iowa Gambling Task. All participants were female, aged between 18 and 60 years and spoke Spanish as their first language. Results showed a negative correlation between 2-AG and cognitive flexibility performance (r = −.37; p<.05). A positive correlation was found between AEA concentrations and both cognitive flexibility (r = .59; p<.05) and decision making performance (r = .23; P<.05). There was no significant correlation between either 2-AG (r = −.17) or AEA (r = −.08) concentrations and inhibition response. These results show, in humans, a relevant modulation of the endocannabinoid system on prefrontal-dependent cognitive functioning. The present study might have significant implications for the underlying executive alterations described in some psychiatric disorders currently associated with endocannabinoids deregulation (namely drug abuse/dependence, depression, obesity and eating disorders). Understanding the neurobiology of their dysexecutive profile might certainly contribute to the development of new treatments and pharmacological approaches. PMID:23840456

  7. Composite structure of SiO2@AgNPs@p-SiNWs for enhanced broadband optical antireflection.

    PubMed

    Lu, Ren; Wang, Yewu; Gu, Lin; Wang, Wei; Fang, Yanjun; Sha, Jian

    2013-07-29

    The composite structure of SiO(2)@AgNPs@p-SiNWs based on silicon nanowires (SiNWs) produced by metal-assisted chemical etching (MaCE) method has been designed to realize the significant reflection suppression over a broad wavelength range (300 - 2500 nm). Especially, the reflectivity of the structure even below 0.3% at a wide range of 620 - 1950 nm can be achieved. It also has been demonstrated that SiO(2) capers play a dominant role in the significant reflection suppression of the composite structure.

  8. Use of agar/glycerol and agar/glycerol/water as a translucent brain simulant for ballistic testing.

    PubMed

    Falland-Cheung, Lisa; Waddell, J Neil; Lazarjan, Milad Soltanipour; Jermy, Mark C; Winter, Taylor; Tong, Darryl; Brunton, Paul A

    2017-01-01

    The suitability of agar/glycerol/water and agar/glycerol mixtures as brain simulants was investigated. Test specimens (n=15) (50x27×37mm) were fabricated for these different mixtures and conditioned to 12°C, 22°C, and 26°C prior to testing. For comparison, fresh deer brain specimens (n=20) were sourced and prepared to the same dimensions as the agar/glycerol(/water) mixtures and conditioned to 12°C and 37°C. High impact tests were carried out with a 0.22-caliber air rifle pellet and a high-speed camera was used to record the projectile as it passed through the specimens, allowing for energy loss and vertical displacement velocity calculation. Although the agar/glycerol/water mixture presented with similar vertical expansion and contraction of the specimens to the warm and cold deer brains, a two-fold decrease of the vertical expansion and contraction was noticed with the agar/glycerol specimens. Also considerably less extrusion of this mixture out of the exit and entry sides after specimen penetration was observed. Of the simulants tested, agar/glycerol/water was the most suitable brain simulant for ballistic testing and impact studies.

  9. Activation of glycerol metabolic pathway by evolutionary engineering of Rhizopus oryzae to strengthen the fumaric acid biosynthesis from crude glycerol.

    PubMed

    Huang, Di; Wang, Ru; Du, Wenjie; Wang, Guanyi; Xia, Menglei

    2015-11-01

    Rhizopus oryzae is strictly inhibited by biodiesel-based by-product crude glycerol, which results in low fumaric acid production. In this study, evolutionary engineering was employed to activate the glycerol utilization pathway for fumaric acid production. An evolved strain G80 was selected, which could tolerate and utilize high concentrations of crude glycerol to produce 14.9g/L fumaric acid with a yield of 0.248g/g glycerol. Key enzymes activity analysis revealed that the evolved strain displayed a significant upregulation in glycerol dissimilation, pyruvate consumption and reductive tricarboxylic acid pathways, compared with the parent strain. Subsequently, intracellular metabolic profiling analysis showed that amino acid biosynthesis, tricarboxylic acid cycle, fatty acid and stress response metabolites accounted for metabolic difference between two strains. Moreover, a glycerol fed-batch strategy was optimized to obtain the highest fumaric acid production of 25.5g/L, significantly increased by 20.9-fold than that of the parent strain of 1.2g/L.

  10. Crenarchaeol: the characteristic core glycerol dibiphytanyl glycerol tetraether membrane lipid of cosmopolitan pelagic crenarchaeota.

    PubMed

    Damsté, Jaap S Sinninghe; Schouten, Stefan; Hopmans, Ellen C; van Duin, Adri C T; Geenevasen, Jan A J

    2002-10-01

    The basic structure and stereochemistry of the characteristic glycerol dibiphytanyl glycerol tetraether (GDGT) membrane lipid of cosmopolitan pelagic crenarchaeota has been identified by high field two-dimensional (2D)-NMR techniques. It contains one cyclohexane and four cyclopentane rings formed by internal cyclisation of the biphytanyl chains. Its structure is similar to that of GDGTs biosynthesized by (hyper)thermophilic crenarchaeota apart from the cyclohexane ring. These findings are consistent with the close phylogenetic relationship of (hyper)thermophilic and pelagic crenarchaeota based 16S rRNA. The latter group inherited the biosynthetic capabilities for a membrane composed of cyclopentane ring-containing GDGTs from the (hyper)thermophilic crenarchaeota. However, to cope with the much lower temperature of the ocean, a small but key step in their evolution was the adjustment of the membrane fluidity by making a kink in one of the bicyclic biphytanyl chains by the formation of a cyclohexane ring. This prevents the dense packing characteristic for the cyclopentane ring-containing GDGTs membrane lipids used by hyperthermophilic crenarchaeota to adjust their membrane fluidity to high temperatures.

  11. The Holocene Records of Glycerol Dialkyl Glycerol Tetraethers From the Northern Chukchi Sea

    NASA Astrophysics Data System (ADS)

    Park, Y.; Yamamoto, M.; Nam, S.; Polyak, L. V.

    2013-12-01

    We analyzed glycerol dialkyl glycerol tetraethers (GDGTs) in Cores HOTRAX 05-01 JPC5 and JPC 8, and ARA02B 01-GC in the northern Chukchi Sea. All of the three cores showed a similar changing pattern in GDGT composition during the Holocene. In the beginning of early Holocene, both isoprenoid and branched GDGT concentrations were low, and BIT and CBT were relatively high. The similar composition is found in modern sediments from the western Arctic Ocean north of 75°N, suggesting that the northern Chukchi Sea was covered by perennial sea ice. GDGT concentration increased, and BIT and CBT decreased during the early Holocene and reached the same level as those in modern sediments at 8 ka. TEX86 and CBT/MBT indices showed millennial-scale variation. We interpret that these proxies did not simply indicate temperatures but were affected by the relative contribution of different sediment sources. Millennial-scale variability likely reflected changes in sediment transport in the northern Chukchi Sea.

  12. Glycerol monolaurate prevents mucosal SIV transmission

    PubMed Central

    Li, Qingsheng; Estes, Jacob D.; Schlievert, Patrick M.; Duan, Lijie; Brosnahan, Amanda J.; Southern, Peter J.; Reilly, Cavan S.; Peterson, Marnie L.; Schultz-Darken, Nancy; Brunner, Kevin G.; Nephew, Karla R.; Pambuccian, Stefan; Lifson, Jeffrey D.; Carlis, John V.; Haase, Ashley T.

    2009-01-01

    While there has been great progress in treating HIV-1 infection1, preventing transmission has thus far proven an elusive goal. Indeed, recent trials of a candidate vaccine and microbicide have been disappointing, both for want of efficacy and concerns about increased rates of transmission2–4. Nonetheless, studies of vaginal transmission in the SIV-rhesus macaque model point to opportunities in the earliest stages of infection where a vaccine or microbicide might be protective, by limiting the expansion of infected founder populations at the portal of entry5, 6. Here we show in this SIV-macaque model, that an outside-in endocervical mucosal signalling system, involving MIP-3α, plasmacytoid dendritic cells and CCR5+cell-attracting chemokines produced by these cells, in combination with the innate immune and inflammatory responses to infection in both cervix and vagina, recruit CD4+T cells to fuel this obligate expansion. We then show that glycerol monolaurate, a widely used antimicrobial compound 7 with inhibitory activity against production of MIP-3α and other proinflammatory cytokines8, can inhibit mucosal signalling and the innate and inflammatory response to HIV-1 and SIV in vitro, and in vivo can protect rhesus macaques from acute infection despite repeated intra-vaginal exposure to high doses of SIV. This novel approach, plausibly linked to interfering with innate host responses that recruit the target cells necessary to establish systemic infection, opens a promising new avenue for development of effective interventions to block HIV-1 mucosal transmission. PMID:19262509

  13. Glycerol monolaurate prevents mucosal SIV transmission.

    PubMed

    Li, Qingsheng; Estes, Jacob D; Schlievert, Patrick M; Duan, Lijie; Brosnahan, Amanda J; Southern, Peter J; Reilly, Cavan S; Peterson, Marnie L; Schultz-Darken, Nancy; Brunner, Kevin G; Nephew, Karla R; Pambuccian, Stefan; Lifson, Jeffrey D; Carlis, John V; Haase, Ashley T

    2009-04-23

    Although there has been great progress in treating human immunodeficiency virus 1 (HIV-1) infection, preventing transmission has thus far proven an elusive goal. Indeed, recent trials of a candidate vaccine and microbicide have been disappointing, both for want of efficacy and concerns about increased rates of transmission. Nonetheless, studies of vaginal transmission in the simian immunodeficiency virus (SIV)-rhesus macaque (Macacca mulatta) model point to opportunities at the earliest stages of infection in which a vaccine or microbicide might be protective, by limiting the expansion of infected founder populations at the portal of entry. Here we show in this SIV-macaque model, that an outside-in endocervical mucosal signalling system, involving MIP-3alpha (also known as CCL20), plasmacytoid dendritic cells and CCR5(+ )cell-attracting chemokines produced by these cells, in combination with the innate immune and inflammatory responses to infection in both cervix and vagina, recruits CD4(+) T cells to fuel this obligate expansion. We then show that glycerol monolaurate-a widely used antimicrobial compound with inhibitory activity against the production of MIP-3alpha and other proinflammatory cytokines-can inhibit mucosal signalling and the innate and inflammatory response to HIV-1 and SIV in vitro, and in vivo it can protect rhesus macaques from acute infection despite repeated intra-vaginal exposure to high doses of SIV. This new approach, plausibly linked to interfering with innate host responses that recruit the target cells necessary to establish systemic infection, opens a promising new avenue for the development of effective interventions to block HIV-1 mucosal transmission.

  14. Glycerol decreases the volume and compressibility of protein interior.

    PubMed

    Priev, A; Almagor, A; Yedgar, S; Gavish, B

    1996-02-20

    The addition of hydrogen-bonded cosolvents to aqueous solutions of proteins is known to modify both thermodynamic and dynamic properties of the proteins in a variety of ways. Previous studies suggest that glycerol reduces the free volume and compressibility of proteins. However, there is no directly measured evidence for that. We have measured the apparent specific volume (V) and adiabatic compressibility (K) of a number of proteins, sugars, and amino acids in water and in 30% glycerol at pH 7.4 and 30 degrees C. The values of V and K in water and their changes induced by glycerol were extrapolated to the limit of infinite solute size. The main results were the following: (a) glycerol decreases V and K of proteins, but increases it for amino acids; (b) the V and K values of the protein interior in water were found to be 0.784 +/- 0.026 mL/g and (12.8 +/- 2.5) x 10(-6) mL/g x atm, where the glycerol reduces these values by 8 and 32%, respectively; (c) the coefficient of adiabatic compressibility of the structural component of proteins affected by the glycerol is estimated to be (50 +/- 10) x 10(-6) atm(-1), which is comparable to that of water. We propose that the glycerol induces a release of the so-called "lubricant" water, which maintains conformational flexibility by keeping apart neighboring segments of the polypeptide chain. This is expected to lead to the collapsing of the voids containing the water as well as to increase intramolecular bonding, which explains the observed effect.

  15. Optical Properties of a Quantum Spin Liquid Candidate Material, κ-(BEDT-TTF)2Ag2(CN)3

    NASA Astrophysics Data System (ADS)

    Nakamura, Yuto; Hiramatsu, Takaaki; Yoshida, Yukihiro; Saito, Gunzi; Kishida, Hideo

    2017-01-01

    We investigated the electronic states of a quantum spin liquid candidate material, κ-(BEDT-TTF)2Ag2(CN)3, using optical methods. In reflectivity measurements, we observed the polarization dependence of electronic transitions, which reflects the crystal structure and anisotropic charge excitation. Raman scattering measurements revealed that the broad magnetic excitation mode is located below 600 cm-1. This spectral feature indicates the spin-liquid nature of the candidate material. The charge-sensitive molecular-vibrational modes observed in infrared and Raman spectra are broader than those of typical BEDT-TTF compounds, which indicate a possibility of dynamic charge fluctuation. By comparing the optical spectra of κ-(BEDT-TTF)2Ag2(CN)3 with a well-investigated spin-liquid candidate κ-(BEDT-TTF)2Cu2(CN)3, we found common optical properties of BEDT-TTF-based spin-liquid candidates. The dynamic fluctuations of charge on a BEDT-TTF dimer are independent of the arrangement of BEDT-TTF molecules and anion layers.

  16. In vitro antibacterial activity of porous TiO2-Ag composite layers against methicillin-resistant Staphylococcus aureus.

    PubMed

    Necula, Bogdan S; Fratila-Apachitei, Lidy E; Zaat, Sebastian A J; Apachitei, Iulian; Duszczyk, Jurek

    2009-11-01

    The aim of this study was the synthesis of a porous TiO(2)-Ag composite coating and assessment of its in vitro bactericidal activity against methicillin-resistant Staphylococcus aureus. The coating was produced by plasma electrolytic oxidation of Ti-6Al-7Nb medical alloy in a calcium acetate/calcium glycerophosphate electrolyte bearing Ag nanoparticles. Following oxidation, the surface of the titanium substrate was converted into the corresponding oxide (TiO(2)) bearing Ca and P species from the electrolyte. In addition, Ag was detected associated with particles present in the oxide layers. The coatings revealed a porous interconnected structure with pores up to 3 microm in size, a threefold increase in roughness and improved wettability relative to the non-oxidized specimens. The composite TiO(2)-Ag coating showed complete killing of methicillin-resistant S. aureus within 24h in all culture conditions, whereas a 1000-fold increase in bacterial numbers was recorded with the ground titanium specimens and the samples oxidized in the absence of Ag nanoparticles.

  17. Engineering of a Glycerol Utilization Pathway for Amino Acid Production by Corynebacterium glutamicum▿

    PubMed Central

    Rittmann, Doris; Lindner, Steffen N.; Wendisch, Volker F.

    2008-01-01

    The amino acid-producing organism Corynebacterium glutamicum cannot utilize glycerol, a stoichiometric by-product of biodiesel production. By heterologous expression of Escherichia coli glycerol utilization genes, C. glutamicum was engineered to grow on glycerol. While expression of the E. coli genes for glycerol kinase (glpK) and glycerol 3-phosphate dehydrogenase (glpD) was sufficient for growth on glycerol as the sole carbon and energy source, additional expression of the aquaglyceroporin gene glpF from E. coli increased growth rate and biomass formation. Glutamate production from glycerol was enabled by plasmid-borne expression of E. coli glpF, glpK, and glpD in C. glutamicum wild type. In addition, a lysine-producing C. glutamicum strain expressing E. coli glpF, glpK, and glpD was able to produce lysine from glycerol as the sole carbon substrate as well as from glycerol-glucose mixtures. PMID:18757581

  18. Crude glycerol-based production of amino acids and putrescine by Corynebacterium glutamicum.

    PubMed

    Meiswinkel, Tobias M; Rittmann, Doris; Lindner, Steffen N; Wendisch, Volker F

    2013-10-01

    Corynebacterium glutamicum possesses genes for glycerol kinase and glycerol-3-phosphate dehydrogenase that were shown to support slow growth with glycerol only when overexpressed from a plasmid. Pure glycerol and crude glycerol from biodiesel factories were tested for growth of recombinant strains expressing glpF, glpK and glpD from Escherichia coli. Some, but not all crude glycerol lots served as good carbon sources. Although the inhibitory compound(s) present in these crude glycerol lots remained unknown, the addition of substoichiometric glucose concentrations (below 10% by weight) enabled the utilization of some of the inhibitory crude glycerol lots. Besides growth, production of the amino acids L-glutamate, L-lysine, L-ornithine and L-arginine as well as of the diamine putrescine based on crude glycerol qualities from biodiesel factories was demonstrated.

  19. Plasticization of a protein-based film by glycerol: a spectroscopic, mechanical, and thermal study.

    PubMed

    Gao, Chunli; Stading, Mats; Wellner, Nikolaus; Parker, Mary L; Noel, Timothy R; Mills, E N Clare; Belton, Peter S

    2006-06-28

    Kafirin, the seed storage protein of the cereal sorghum, is highly homologous with the maize storage protein zein. The effects of plasticisation of a kafirin film by glycerol in the absence of water were examined by a combination of spectroscopic (NMR and infrared), rheological, and calorimetric methods. The results suggest that at low glycerol levels the glycerol is absorbed onto and possibly into the protein. Increasing the level of glycerol increases the motion of the protein and changes the protein conformation. There are corresponding changes of the mechanical properties of protein films. At 40% (w/w) of glycerol, two glass transition temperatures were observed, one of which corresponded to the glass transition temperature of pure glycerol. This result indicates that at this level of plasticizer there are sufficient glycerol/glycerol interactions occurring to allow a separate glass formation process for glycerol.

  20. Enhanced apatite-forming ability and antibacterial activity of porous anodic alumina embedded with CaO-SiO2-Ag2O bioactive materials.

    PubMed

    Ni, Siyu; Li, Xiaohong; Yang, Pengan; Ni, Shirong; Hong, Feng; Webster, Thomas J

    2016-01-01

    In this study, to provide porous anodic alumina (PAA) with bioactivity and anti-bacterial properties, sol-gel derived bioactive CaO-SiO2-Ag2O materials were loaded onto and into PAA nano-pores (termed CaO-SiO2-Ag2O/PAA) by a sol-dipping method and subsequent calcination of the gel-glasses. The in vitro apatite-forming ability of the CaO-SiO2-Ag2O/PAA specimens was evaluated by soaking them in simulated body fluid (SBF). The surface microstructure and chemical property before and after soaking in SBF were characterized. Release of ions into the SBF was also measured. In addition, the antibacterial properties of the samples were tested against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The results showed that CaO-SiO2-Ag2O bioactive materials were successfully decorated onto and into PAA nano-pores. In vitro SBF experiments revealed that the CaO-SiO2-Ag2O/PAA specimens dramatically enhanced the apatite-forming ability of PAA in SBF and Ca, Si and Ag ions were released from the samples in a sustained and slow manner. Importantly, E. coli and S. aureus were both killed on the CaO-SiO2-Ag2O/PAA (by 100%) samples compared to PAA controls after 3 days of culture. In summary, this study demonstrated that the CaO-SiO2-Ag2O/PAA samples possess good apatite-forming ability and high antibacterial activity causing it to be a promising bioactive coating candidate for implant materials for orthopedic applications.

  1. Microbial conversion of glycerol: present status and future prospects.

    PubMed

    Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

    2012-09-01

    Biodiesel has emerged as a potential alternate renewable liquid fuel in the past two decades. Total annual production of biodiesel stands at 6.96 million tons and 11.2 million tons in USA and Europe, respectively. In other countries, Asia and Latin America, biodiesel production has increased at unprecedented rate. Despite this, the economy of biodiesel is not attractive. An obvious solution for boosting the economy of the biodiesel industry is to look for markets for side products of the transesterification process of biodiesel synthesis. The main by-product is glycerol. However, this glycerol is contaminated with alkali/acid catalyst and alcohol, and thus, is not useful for conventional applications such as in toothpaste, drugs, paints and cosmetics. Conversion of this glycerol to value-added product is a viable solution for effective and economic utilization, which would also generate additional revenue for the biodiesel industry. Intensive research has taken place in area of conversion of glycerol to numerous products. The conventional catalytic route of glycerol transformation employs prohibitively harsh conditions of temperature and pressure, and thus, has slim potential for large-scale implementation. In addition, the selectivity of the process is rather small with formation of many undesired side products. The bioconversion processes, on the other hand, are highly selective although with slower kinetics. In this review, we have given an assessment and overview of the literature on bioconversion of glycerol. We have assessed as many as 23 products from glycerol bioconversion, and have reviewed the literature in terms of microorganism used, mode of fermentation, type of fermentor, yield and productivity of the process and recovery/purification of the products. The metabolic pathway of conversion of glycerol to various products has been discussed. We have also pondered over economic and engineering issues of large-scale implementation of process and have

  2. Titanium glycerolate-based electrorheological fluids with stable properties

    NASA Astrophysics Data System (ADS)

    Dong, Xufeng; Zhao, Hong; Qi, Min; Tao, Wanyong

    2014-04-01

    Titanium glycerolate (TiGly) particles were prepared with different molar ratios of glycerol to tetrabutyltitanate (TBOT) (glycerol/TBOT = 2, 2.5, and 3) by a simple precipitation method. For comparison, titanium propanediol (TiPro) particles were prepared with 1,3-propanediol and TBOT (propanediol/TBOT = 2) by the same route. The composition and morphology of the four kinds of particles were characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), respectively. The results indicate that the secondary hydroxyl groups originating from glycerolate are doped into the TiGly particles, and the four kinds of particles present different morphology. The suspensions prepared with TiGly particles by 60% weight fraction and silicone oil show significant electrorheological (ER) performance, while the TiPro particles-based fluid with the same particles fraction present weak ER properties. Constant shear rate and step-function electric field pulses were applied to investigate the stability of the ER fluids. The TiGly particles synthesized with the molar ratio of glycerol to TBOT equaling 2.5 exhibit significant (˜40 kPa at 5 kV mm-1) and stable ER activity.

  3. Development of glycerol/O 2 biofuel cell

    NASA Astrophysics Data System (ADS)

    Arechederra, Robert L.; Treu, Becky L.; Minteer, Shelley D.

    Glycerol is an attractive fuel for a fuel cell, because it is non-toxic, non-volatile, non-flammable, has high energy density, and is abundant due to the fact that it is a byproduct of biodiesel production. However, it has not been an effective fuel for low temperature, precious metal catalyzed fuel cells. In this paper, we describe the use of glycerol as a fuel in an enzymatic biofuel cell. An alcohol dehydrogenase and aldehyde dehydrogenase-based bioanode has been developed that oxidizes glycerol, a safe high energy density fuel. Glycerol/O 2 biofuel cells employing these bioanodes have yielded power densities of up to 1.21 mW cm -2, and have the ability to operate at 98.9% fuel concentrations. Previous biofuel cells could not operate effectively at high fuel concentrations due to the nature of the solid fuel such as sugar or the solvent characteristics of fuels such as lower aliphatic alcohols. The glycerol/O 2 biofuel cell provides improved power densities compared to ethanol biofuel cells due to ability to more completely oxidize the fuel.

  4. Determination of optimal glycerol concentration for optical tissue clearing

    NASA Astrophysics Data System (ADS)

    Youn, Eungjun; Son, Taeyoon; Kim, Han-Sung; Jung, Byungjo

    2012-02-01

    The laser scattering in tissue is significant in diagnostic and therapeutic purposes of laser. Many studies have been conducted to minimize laser scattering in tissue and therefore, to maximize the clinical efficacy by enhancing photon density. Optical clearing agents (OCAs) have been employed for optical tissue clearing (OTC). This study was aimed to investigate the optimal concentration of an OCA, glycerol, in topical application,, so that it can be utilized for clinical diagnosis and therapy in dermatology. Glycerol was topically applied to avoid possible edema caused by dermal injection. The effect of OTC was quantitatively evaluated as a function of the concentration of glycerol with various methods. Optical methods such as optical coherence tomography (OCT) and an integrating sphere were used to assess the enhancement of light penetration depth and refractive index matching. In addition, a non-optical method, ultrasound scanner, was utilized to evaluate quantitatively collagen dissociation. The results revealed that 70 % glycerol was the optimal concentration of OTC for topical application. This study may provide a guideline regarding to the use of glycerol for optimal diagnostic and therapeutic effects in dermatology.

  5. Effect of NaCl on the accumulation of glycerol by three Aspergillus species.

    PubMed

    Zidan, M A; Abdel-Mallek, A Y

    1987-01-01

    The accumulation of glycerol was investigated in three Aspergillus species, A. niger, A. ochraceus and A. tamarii after being grown in media containing different NaCl concentrations. Intra-extracellular as well as total glycerol were markedly accumulated by the three organisms in response to increased salinity. However, at salinity levels of 10-14% NaCl, extracellular glycerol was somewhat lowered. In addition, it was found that the maximum accumulation of glycerol in A. niger and A. tamarii was reached within the first 10 hours after salinization. However, after desalinization, the extracellular glycerol was continuously increased within the first 6 hours at the expense of intracellular glycerol.

  6. Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids in hot springs of yellowstone national park.

    PubMed

    Schouten, Stefan; van der Meer, Marcel T J; Hopmans, Ellen C; Rijpstra, W Irene C; Reysenbach, Anna-Louise; Ward, David M; Sinninghe Damsté, Jaap S

    2007-10-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are core membrane lipids originally thought to be produced mainly by (hyper)thermophilic archaea. Environmental screening of low-temperature environments showed, however, the abundant presence of structurally diverse GDGTs from both bacterial and archaeal sources. In this study, we examined the occurrences and distribution of GDGTs in hot spring environments in Yellowstone National Park with high temperatures (47 to 83 degrees C) and mostly neutral to alkaline pHs. GDGTs with 0 to 4 cyclopentane moieties were dominant in all samples and are likely derived from both (hyper)thermophilic Crenarchaeota and Euryarchaeota. GDGTs with 4 to 8 cyclopentane moieties, likely derived from the crenarchaeotal order Sulfolobales and the euryarchaeotal order Thermoplasmatales, are usually present in much lower abundance, consistent with the relatively high pH values of the hot springs. The relative abundances of cyclopentane-containing GDGTs did not correlate with in situ temperature and pH, suggesting that other environmental and possibly genetic factors play a role as well. Crenarchaeol, a biomarker thought to be specific for nonthermophilic group I Crenarchaeota, was also found in most hot springs, though in relatively low concentrations, i.e., <5% of total GDGTs. Its abundance did not correlate with temperature, as has been reported previously. Instead, the cooccurrence of relatively abundant nonisoprenoid GDGTs thought to be derived from soil bacteria suggests a predominantly allochthonous source for crenarchaeol in these hot spring environments. Finally, the distribution of bacterial branched GDGTs suggests that they may be derived from the geothermally heated soils surrounding the hot springs.

  7. Amperometric triglyceride bionanosensor based on nanoparticles of lipase, glycerol kinase, glycerol-3-phosphate oxidase.

    PubMed

    Pundir, C S; Aggarwal, V

    2017-01-15

    The nanoparticles (NPs) aggregates of lipase from porcine pancreas, glycerol kinase (GK) from Cellulomonas sp. and glycerol-3-phosphate oxidase (GPO) from Aerococcus viridanss were prepared by desolvation and glutaraldehyde crosslinking and functionalized by cysteamine. These enzyme nanoparticles (ENPs) were characterized by transmission electron microscopy (TEM) and Fourier transform infra red (FTIR) spectroscopy. The functionalzed ENPs aggregates were co-immobilized covalently onto polycrystalline Au electrode through thiolated bond. An improved amperometric triglyceride (TG) bionanosensor was constructed using this ENPs modified Au electrode as working electrode. Biosensor showed optimum current at 1.2 V within 5s, at pH 6.5 and 35 °C.A linear relationship was obtained between current (mA) and triolein concentration in lower concentration range,10-100 mg/dL and higher concentration range, 100-500 mg/dL. Limit of detection (LOD) of bionanosensor was 1.0 μg/ml. Percent analytical recovery of added trolein (50 and 100 mg/dL) in serum was 95.2 ± 0.5 and 96.0 ± 0.17. Within and between batch coefficients of variation (CV) were 2.33% and 2.15% respectively. A good correlation (R(2) = 0.99) was obtained between TG values in sera measured by present biosensor and standard enzymic colorimetric method with the regression equation: y= (0.993x + 0.967). ENPs/Au electrode was used 180 times over a period of 3 months with 50% loss in its initial activity, when stored dry at 4 °C.

  8. Source, settling and degradation of branched glycerol dialkyl glycerol tetraethers in the marine water column

    NASA Astrophysics Data System (ADS)

    Yamamoto, Masanobu; Shimamoto, Akifumi; Fukuhara, Tatsuo; Tanaka, Yuichiro

    2016-10-01

    Branched glycerol dialkyl glycerol tetraethers (branched GDGTs) are commonly found in distal marine sediments. However, their presence in the water column, source and delivery process are not fully understood. In this study, we examined seasonal and depth variation in the flux of branched GDGTs in sinking particles and underlying sediment at 39°N, 147°E in the mid-latitude NW Pacific from November 1997 to August 1999. Branched GDGTs showed synchronous variation in their sinking flux at different depths, and the variation was similar to that of lithogenic material of eolian dust origin. Their degrees of cyclization and methylation were nearly constant and bear some resemblance to those of alkaline soils. This suggests that westerly winds transport branched GDGTs to the study site via the atmosphere from continental Asia. The sinking flux of branched GDGTs was higher in 1999 than in 1998, presumably reflecting changes in the migration path of Asian dust in response to the El Niño-Southern Oscillation. Synchronous variation in branched GDGT concentrations at different depths implies rapid vertical transport of branched GDGTs to deep water with a sinking velocity exceeding 260 m d-1. The sinking flux of the branched GDGTs decreased with increasing depth, but the rate of decrease was much smaller than those of other compounds. The preservation efficiency of branched GDGTs was 3.5-6.4% of surface inputs at the water-sediment interface, which is much higher than those of isoprenoid GDGTs (1.0-1.3%) and other compounds. The branched and isoprenoid tetraether (BIT) index values were extremely low (i.e. <0.0015) in comparison with any other studies so far. The BIT values in the surface sediment were five times higher than those in sinking particles, which is attributed to the preferential preservation of branched GDGTs in oxic environments.

  9. In situ production of branched glycerol dialkyl glycerol tetraethers in a great basin hot spring (USA)

    PubMed Central

    Zhang, Chuanlun L.; Wang, Jinxiang; Dodsworth, Jeremy A.; Williams, Amanda J.; Zhu, Chun; Hinrichs, Kai-Uwe; Zheng, Fengfeng; Hedlund, Brian P.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are predominantly found in soils and peat bogs. In this study, we analyzed core (C)-bGDGTs after hydrolysis of polar fractions using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry and analyzed intact P-bGDGTs using total lipid extract (TLE) without hydrolysis by liquid chromatography-electrospray ionization-multiple stage mass spectrometry. Our results show multiple lines of evidence for the production of bGDGTs in sediments and cellulolytic enrichments in a hot spring (62–86°C) in the Great Basin (USA). First, in situ cellulolytic enrichment led to an increase in the relative abundance of hydrolysis-derived P-bGDGTs over their C-bGDGT counterparts. Second, the hydrolysis-derived P- and C-bGDGT profiles in the hot spring were different from those of the surrounding soil samples; in particular, a monoglycosidic bGDGT Ib containing 13,16-dimethyloctacosane and one cyclopentane moiety was detected in the TLE but it was undetectable in surrounding soil samples even after sample enrichments. Third, previously published 16S rRNA gene pyrotag analysis from the same lignocellulose samples demonstrated the enrichment of thermophiles, rather than mesophiles, and total bGDGT abundance in cellulolytic enrichments correlated with the relative abundance of 16S rRNA gene pyrotags from thermophilic bacteria in the phyla Bacteroidetes, Dictyoglomi, EM3, and OP9 (“Atribacteria”). These observations conclusively demonstrate the production of bGDGTs in this hot spring; however, the identity of organisms that produce bGDGTs in the geothermal environment remains unclear. PMID:23847605

  10. Preparation of Ag deposited TiO2 (Ag/TiO2) composites and investigation on visible-light photocatalytic degradation activity in magnetic field

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Ma, C. H.; Wang, J.; Li, S. G.; Li, Y.

    2014-12-01

    In this study, Ag deposited TiO2 (Ag/TiO2) composites were prepared by three different methods (Ultraviolet Irradiation Deposition (UID), Vitamin C Reduction (VCR) and Sodium Borohydride Reduction (SBR)) for the visible-light photocatalytic degradation of organic dyes in magnetic field. And then the prepared Ag deposited TiO2 (Ag/TiO2) composites were characterized physically by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The visible-light photocatalytic activities of these three kinds of Ag deposited TiO2 (Ag/TiO2) composites were examined and compared through the degradation of several organic dyes under visible-light irradiation in magnetic field. In addition, some influence factors such as visible-light irradiation time, organic dye concentration, revolution speed, magnetic field intensity and organic dye kind on the visible-light photocatalytic activity of Ag deposited TiO2 (Ag/TiO2) composite were reviewed. The research results showed that the presence of magnetic field significantly enhanced the visible-light photocatalytic activity of Ag deposited TiO2 (Ag/TiO2) composites and then contributed to the degradation of organic dyes.

  11. Investigation of ZnS-SiO2/Ag/ZnS-SiO2 as high stable transparent and conductive multilayer films

    NASA Astrophysics Data System (ADS)

    Long, Guoyun; Geng, Yongyou

    2012-12-01

    Novel transparent conductive ZnS-SiO2/Ag/ZnS-SiO2 multilayer films were prepared on K9 glass substrates by magnetron sputtering at room temperature. The structure of ZnS-SiO2/Ag/ZnS-SiO2 multilayer films were theoretically designed and the optimal thickness of each layer was determined (45 nm/11 nm/45 nm). To obtain better optical and electrical properties, the ZnS-SiO2/Ag/ZnS-SiO2 samples were annealed at various temperatures. The optical, electrical, and structural characteristics of the ZnS-SiO2/Ag/ZnS-SiO2 multilayer films were then investigated. The results show that when the annealing temperature was 200 °C, the sample exhibited a low sheet resistance of 9.7 Ω/sq and a high optical transmittance of 88.4%. For the sample annealed at 200 °C, the average transmittance in the visible range (380-780 nm) was calculated and determined as 84.1%. The effects of humidity and temperature on the samples were assessed by an accelerated aging test. The results demonstrate the high damp heat stability of ZnS-SiO2/Ag/ZnS-SiO2 multilayer films.

  12. Random lasing from cholesteric liquid crystal microspheres dispersed in glycerol.

    PubMed

    Li, Yong; Luo, Dan; Chen, Rui

    2016-11-01

    We demonstrate random lasing from a scattering system formed by a cholesteric liquid crystal dispersed in glycerol. Strong scattering of light is produced from the interference between the cholesteric liquid crystal microsphere and glycerol and leads to random lasing. The optical properties of random lasing, such as intensity, threshold, and the temperature effect on lasing emission are demonstrated. The random laser is distinguished from the band-edge laser generated within the cholesteric liquid crystal microspheres by analyzing the positions of the photonic band-edge of the cholesteric liquid crystal and the photoluminescence of the doped laser dye. The random laser from cholesteric liquid crystal microspheres in glycerol possesses a simple fabrication process, small volume, and low threshold, which enable it to be used in speckle-free imaging, target identification, biomedicine, document coding, and other photonic devices.

  13. Ru/FTO: Heterogeneous catalyst for glycerol hydrogenolysis

    NASA Astrophysics Data System (ADS)

    Samad, Wan Zurina; Isahak, Wan Nor Roslam Wan; Liew, Kin Hong; Nordin, Norazzizi; Yarmo, Mohd Ambar; Yusop, Muhammad Rahimi

    2014-09-01

    An introduction of Fluorine-doped tin oxide (FTO) as new catalyst support with Ru metal had enhanced the conversion and selectivity for glycerol hydrogenolysis. A small cluster of Ru were highly dispersed and intercalated over FTO via simple chemical mixture and reduction method. In comparison with various metal (Pd, Os, Cu), Ru/FTO catalyst showed the highest conversion (100%) and highly selectivity of 1,2-propanediol (94%) in the hydrogenolysis of glycerol. The reaction was optimally conducted at 150 °C, 20 bar of H2 pressure and at 8 hours. Ru/FTO catalyst was ascribed as active catalyst due to the amphoteric sites of FTO and small size of Ru metal. This provides high surface concentration of reduction process that involves the chemical bond dissociation in the glycerol hydrogenolysis.

  14. Superlubricity achieved with mixtures of acids and glycerol.

    PubMed

    Li, Jinjin; Zhang, Chenhui; Ma, Liran; Liu, Yuhong; Luo, Jianbin

    2013-01-08

    In this work, superlubricity between glass and Si(3)N(4) surfaces lubricated by mixtures of acid solutions and glycerol solutions has been found by using a traditional tribometer. Ultralow friction coefficients of between 0.004 and 0.006 were obtained after a running-in period. Related experiments indicate that the hydrogen ions in the mixtures play an important role in achieving superlubricity. Moreover, the ultralow friction is also closely related to the pH value of the acid and the concentration of glycerol. According to these results, the possible superlubricity mechanism has been revealed, which is attributed to a fluid-hydrated water layer between the hydrogen-bonded networks of glycerol and water molecules on the positively charged surfaces.

  15. Production of 1,2-propanediol from glycerol in Saccharomyces cerevisiae.

    PubMed

    Jung, Joon-Young; Yun, Hyun Shik; Lee, Jinwon; Oh, Min-Kyu

    2011-08-01

    Glycerol has become an attractive carbon source in the biotechnology industry owing to its low price and reduced state. However, glycerol is rarely used as a carbon source in Saccharomyces cerevisiae because of its low utilization rate. In this study, we used glycerol as a main carbon source in S. cerevisiae to produce 1,2-propanediol. Metabolically engineered S. cerevisiae strains with overexpression of glycerol dissimilation pathway genes, including glycerol kinase (GUT1), glycerol 3-phosphate dehydrogenase (GUT2), glycerol dehydrogenase (gdh), and a glycerol transporter gene (GUP1), showed increased glycerol utilization and growth rate. More significant improvement of glycerol utilization and growth rate was accomplished by introducing 1,2-propanediol pathway genes, mgs (methylglyoxal synthase) and gldA (glycerol dehydrogenase) from Escherichia coli. By engineering both glycerol dissimilation and 1,2-propanediol pathways, the glycerol utilization and growth rate were improved 141% and 77%, respectively, and a 2.19 g 1,2- propanediol/l titer was achieved in 1% (v/v) glycerolcontaining YEPD medium in engineered S. cerevisiae.

  16. JZL184 is anti-hyperalgesic in a murine model of cisplatin-induced peripheral neuropathy

    PubMed Central

    Khasabova Iryna, A; Yao, Xu; Paz, Justin; Lewandowski Cutler, T; Lindberg Amy, E; Coicou, Lia; Burlakova, Natasha; Simone Don, A; Seybold Virginia, S

    2014-01-01

    Cisplatin has been used effectively to treat a variety of cancers but its use is limited by the development of painful peripheral neuropathy. Because the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG) is anti-hyperalgesic in several preclinical models of chronic pain, the anti-hyperalgesic effect of JZL184, an inhibitor of 2-AG hydrolysis, was tested in a murine model of cisplatin-induced hyperalgesia. Systemic injection of cisplatin (1 mg/kg) produced mechanical hyperalgesia when administered daily for 7 days. Daily peripheral administration of a low dose of JZL184 in conjunction with cisplatin blocked the expression of mechanical hyperalgesia. Acute injection of a cannabinoid (CB)-1 but not a CB2 receptor antagonist reversed the anti-hyperalgesic effect of JZL184 indicating that downstream activation of CB1 receptors suppressed the expression of mechanical hyperalgesia. Components of endocannabinoid signaling in plantar hind paw skin and lumbar dorsal root ganglia (DRGs) were altered by treatments with cisplatin and JZL184. Treatment with cisplatin alone reduced levels of 2-AG and AEA in skin and DRGs as well as CB2 receptor protein in skin. Combining treatment of JZL184 with cisplatin increased 2-AG in DRGs compared to cisplatin alone but had no effect on the amount of 2-AG in skin. Evidence that JZL184 decreased the uptake of [3H]AEA into primary cultures of DRGs at a concentration that also inhibited the enzyme fatty acid amide hydrolase, in conjunction with data that 2-AG mimicked the effect of JZL184 on [3H]AEA uptake support the conclusion that AEA most likely mediates the anti-hyperalgesic effect of JZL184 in this model. PMID:25304184

  17. Endocannabinoids decrease neuropathic pain-related behavior in mice through the activation of one or both peripheral CB₁ and CB₂ receptors.

    PubMed

    Desroches, Julie; Charron, Sophie; Bouchard, Jean-François; Beaulieu, Pierre

    2014-02-01

    The two most studied endocannabinoids are anandamide (AEA), principally catalyzed by fatty-acid amide hydrolase (FAAH), and 2-arachidonoyl glycerol (2-AG), mainly hydrolyzed by monoacylglycerol lipase (MGL). Inhibitors targeting these two enzymes have been described, including URB597 and URB602, respectively. Several recent studies examining the contribution of CB₁ and/or CB₂ receptors on the peripheral antinociceptive effects of AEA, 2-AG, URB597 and URB602 in neuropathic pain conditions using either pharmacological tools or transgenic mice separately have been reported, but the exact mechanism is still uncertain. Mechanical allodynia and thermal hyperalgesia were evaluated in 436 male C57BL/6, cnr1KO and cnr2KO mice in the presence or absence of cannabinoid CB₁ (AM251) or CB₂ (AM630) receptor antagonists in a mouse model of neuropathic pain. Peripheral subcutaneous injections of AEA, 2-AG, WIN55,212-2 (WIN; a CB₁/CB₂ synthetic agonist), URB597 and URB602 significantly decreased mechanical allodynia and thermal hyperalgesia. These effects were inhibited by both cannabinoid antagonists AM251 and AM630 for treatments with 2-AG, WIN and URB602 but only by AM251 for treatments with AEA and URB597 in C57BL/6 mice. Furthermore, the antinociceptive effects for AEA and URB597 were observed in cnr2KO mice but absent in cnr1KO mice, whereas the effects of 2-AG, WIN and URB602 were altered in both of these transgenic mice. Complementary genetic and pharmacological approaches revealed that the anti-hyperalgesic effects of 2-AG and URB602 required both CB₁ and CB₂ receptors, but only CB₂ receptors mediated its anti-allodynic actions. The antinociceptive properties of AEA and URB597 were mediated only by CB₁ receptors.

  18. 2H NMR studies of glycerol dynamics in protein matrices.

    PubMed

    Herbers, C R; Sauer, D; Vogel, M

    2012-03-28

    We use (2)H NMR spectroscopy to investigate the rotational motion of glycerol molecules in matrices provided by the connective tissue proteins elastin and collagen. Analyzing spin-lattice relaxation, line-shape properties, and stimulated-echo decays, we determine the rates and geometries of the motion as a function of temperature and composition. It is found that embedding glycerol in an elastin matrix leads to a mild slowdown of glycerol reorientation at low temperatures and glycerol concentrations, while the effect vanishes at ambient temperatures or high solvent content. Furthermore, it is observed that the nonexponential character of the rotational correlation functions is much more prominent in the elastin matrix than in the bulk liquid. Results from spin-lattice relaxation and line shape measurements indicate that, in the mixed systems, the strong nonexponentiality is in large part due to the existence of distributions of correlation times, which are broader on the long-time flank and, hence, more symmetric than in the neat system. Stimulated-echo analysis of slow glycerol dynamics reveals that, when elastin is added, the mechanism for the reorientation crosses over from small-angle jump dynamics to large-angle jump dynamics and the geometry of the motion changes from isotropic to anisotropic. The results are discussed against the background of present and previous findings for glycerol and water dynamics in various protein matrices and compared with observations for other dynamically highly asymmetric mixtures so as to ascertain in which way the viscous freezing of a fast component in the matrix of a slow component differs from the glassy slowdown in neat supercooled liquids.

  19. Haemodynamic and cerebrovascular responses to glycerol infusion in dogs.

    PubMed

    Chen, J L; Wang, Y C; Wang, J Y

    1989-11-01

    1. The response of cerebral blood vessels to hyperosmolar agents in vivo remains controversial, and little is known about the effect of glycerol on cerebral vessels. In this study we investigated the cerebrovascular response to intravenous administration of glycerol (1 g/kg, infused over 25 min) in dogs under pentobarbital anaesthesia. 2. intracranial pressure, systemic arterial pressure, mean arterial blood pressure, serum osmolarity and packed cell volume were continuously monitored, and blood gases were checked frequently. Through a parietal cranial window, pial vessel diameter was measured by means of a surgical microscope and a video image-analyser. 3. Pial vessel diameter increased gradually with a maximum at 30 min after the beginning of glycerol infusion. The maximum increase in diameter in small (less than or equal to 100 microns) vessels was 14.3%, whereas that in large (greater than 100 microns) vessels was 10.3%. There was only a slight increase (less than 4%) in pial vessel diameter in vehicle-infused animals. The intracranial pressure decreased drastically after glycerol infusion, whereas the mean arterial blood pressure remained constant. There were correlations between the rise in serum osmolarity, fall in packed cell volume and vasodilatation, indicating that glycerol caused vasodilatation accompanied by plasma volume expansion. 4. Our data suggest that glycerol produces cerebral vasodilatation, which might be beneficial in cerebral ischaemia and vasospasm, in addition to its intracranial pressure-reducing effect on normal or oedematous brain. The degree of vasodilatation was not sufficient to affect the predominant intracranial pressure drop resulting from cerebral dehydration.

  20. 2H NMR studies of glycerol dynamics in protein matrices

    NASA Astrophysics Data System (ADS)

    Herbers, C. R.; Sauer, D.; Vogel, M.

    2012-03-01

    We use 2H NMR spectroscopy to investigate the rotational motion of glycerol molecules in matrices provided by the connective tissue proteins elastin and collagen. Analyzing spin-lattice relaxation, line-shape properties, and stimulated-echo decays, we determine the rates and geometries of the motion as a function of temperature and composition. It is found that embedding glycerol in an elastin matrix leads to a mild slowdown of glycerol reorientation at low temperatures and glycerol concentrations, while the effect vanishes at ambient temperatures or high solvent content. Furthermore, it is observed that the nonexponential character of the rotational correlation functions is much more prominent in the elastin matrix than in the bulk liquid. Results from spin-lattice relaxation and line shape measurements indicate that, in the mixed systems, the strong nonexponentiality is in large part due to the existence of distributions of correlation times, which are broader on the long-time flank and, hence, more symmetric than in the neat system. Stimulated-echo analysis of slow glycerol dynamics reveals that, when elastin is added, the mechanism for the reorientation crosses over from small-angle jump dynamics to large-angle jump dynamics and the geometry of the motion changes from isotropic to anisotropic. The results are discussed against the background of present and previous findings for glycerol and water dynamics in various protein matrices and compared with observations for other dynamically highly asymmetric mixtures so as to ascertain in which way the viscous freezing of a fast component in the matrix of a slow component differs from the glassy slowdown in neat supercooled liquids.

  1. Glycerol and bioglycerol conversion in supercritical water for hydrogen production.

    PubMed

    Yu-Wu, Q M; Weiss-Hortala, E; Barna, R; Boucard, H; Bulza, S

    2012-01-01

    Catalytic transesterification of vegetable oils leads to biodiesel and an alkaline feed (bioglycerol and organic residues, such as esters, alcohols. . .). The conversion ofbioglycerol into valuable organic molecules represents a sustainable industrial process leading to the valorization of a renewable organic resource. The physicochemical properties in the supercritical domain (T > 374 degrees C, P > 22.1 MPa) transform water into a solvent for organics and a reactant favouring radical reactions. In this context, the conversion ofbioglycerol in supercritical water (SCW) into platform molecules and/or high energetic gases (hydrogen, hydrocarbons) could represent an interesting valorization process. The reported research results concern the conversion of bioglycerol compared to pure glycerol. The experiments have been done in batch autoclaves (5 ml and 500 ml stirred). Solutions of pure (5 or 10 wt%) and crude (3.5 wt%) glycerol have been processed with or without catalyst (K2CO3 1.5 wt%) in the range of 450-600 degrees C. The molecular formula of bioglycerol was determined as C4.3H9.7O1.8Na0.1Si0.08. Glycerol was partially decomposed in the batch systems during the heating (42% before reaching 420 degrees C) and some intermediates (propanediol, ethylene glycol . . .) were quantified, leading to a proposition of a reaction pathway. Acrolein, a valuable platform molecule, was mainly produced in the absence of catalyst. No solid phase was recovered after SCW conversion of pure and bioglycerol in batch reactors. The optimal parameters for gasification were 600 degrees C, 25 MPa for bioglycerol and 525 degrees C, 25 MPa, for pure glycerol. In these operating conditions, 1 kg of pure or bioglycerol leads to 15 and, respectively, 10 mol of hydrogen. Supercritical water gasification of crude glycerol favoured the generation of light hydrocarbons, while pure glycerol promoted H2 production. SCW conversion of glycerol (pure and crude) allows to obtain simultaneously energetic

  2. Propylene from renewable resources: catalytic conversion of glycerol into propylene.

    PubMed

    Yu, Lei; Yuan, Jing; Zhang, Qi; Liu, Yong-Mei; He, He-Yong; Fan, Kang-Nian; Cao, Yong

    2014-03-01

    Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene.

  3. Dielectric and specific heat relaxations in vapor deposited glycerol

    NASA Astrophysics Data System (ADS)

    Kasina, A.; Putzeys, T.; Wübbenhorst, M.

    2015-12-01

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk Tg and subsequent cooling/reheating revealed a step-wise increase in cp by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at -75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of "MROL glycerol" to its "normal" (ordinary liquid, OL) state revealed a second, small (˜2%) increase of the glassy cp, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τcal from that of normal "bulk" glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the existence of rigid polar clusters (RPCs) and

  4. Pulse loading of glycerol by electric explosion of wire

    NASA Astrophysics Data System (ADS)

    Uvarov, S. V.; Bannikova, I. A.; Naimark, O. B.

    2015-11-01

    A series of experiments was carried out to investigate the relaxation properties of glycerol under shock-wave loading. The strain rates at the compression wave front were in the range of 105-107 s-1. A modified version of the wire explosion set-up was used. Free surface velocity profiles were recorded by VISAR with fiber-optic sensor. We found that the glycerol exhibits the non-Newtonian liquid behavior: viscosity is higher at the high strain rate. Strain rate at the compressive wave front is found to be dependent on the wave amplitude in power of 1.3.

  5. Cryoprotective effect of different glycerol concentrations on domestic cat spermatozoa.

    PubMed

    Villaverde, Ana Izabel S Balbin; Fioratti, Eduardo G; Penitenti, Marcimara; Ikoma, Maura R V; Tsunemi, Miriam H; Papa, Frederico O; Lopes, Maria D

    2013-10-15

    Cryopreservation of spermatozoa is a pivotal tool in assisted reproduction, and studies aiming to establish optimal freezing/thawing protocols are essential to enhance sperm survival. The objectives of the present study were to (1) compare the cryoprotective efficiency of three different glycerol concentrations (3%, 5%, and 7%) on the basis of post-thaw sperm quality and (2) investigate whether the incidence of morphologically abnormal sperm in fresh samples is related to cryodamage sensitivity. Semen was collected from six tomcats using an artificial vagina (total 18 ejaculates). Each ejaculate was diluted using Tris-egg yolk-based extender (TEY), evaluated, equally divided into three aliquots, and rediluted using TEY with and without glycerol to achieve final concentrations of 3%, 5%, and 7%. Samples were loaded into 0.25 mL straws, equilibrated for 60 minutes at 5 °C, frozen, and then thawed at 46 °C for 12 seconds. Fresh and frozen-thawed samples were evaluated for sperm motion parameters (computer-assisted sperm analysis), plasma membrane integrity (PMI; propidium iodide and carboxyfluorescein diacetate), and DNA integrity (acridine orange). Plasma and acrosomal membrane integrity were assessed by flow cytometry (propidium iodide and fluorescein isothiocyanate-conjugated pea (Pisum sativum) agglutinin) immediately after thawing. Sperm motion parameters were also evaluated at 30 and 60 minutes of postincubation. For all treatment groups, cryopreservation significantly impaired the PMI and sperm motion parameters, except for straightness and amplitude of lateral head displacement. DNA integrity showed a slight reduction (P < 0.05) when 3% glycerol was used. The percentage of total motility, progressive motility, and rapid spermatozoa were significantly lower immediately after thawing and up to 60 minutes of incubation for the 3% glycerol group when compared with 5% and 7%. No difference (P > 0.05) was found for PMI, acrosome integrity, and DNA integrity among

  6. SET kinetics of electrochemical metallization cells: influence of counter-electrodes in SiO2/Ag based systems

    NASA Astrophysics Data System (ADS)

    Lübben, M.; Menzel, S.; Park, S. G.; Yang, M.; Waser, R.; Valov, I.

    2017-03-01

    The counter-electrode material in resistively switching electrochemical metallization cells (ECMs) is a crucial factor influencing the nucleation of conductive filaments, the equilibrium electrode potentials, and kinetics in the devices, and hence the overall switching characteristics. Here, we demonstrate the influence of the counter-electrode (CE) material on the SET events and the importance of appropriate choice and combination of materials. The counter-electrode material influences the counter-electrode processes at the CE/insulator interface and consequently determines the metal ion concentration in the cells. We measured the switching kinetics for SiO2/Ag based ECM cells using different counter-electrode materials with different electrocatalytic activities towards water reduction, namely platinum, ruthenium, and iridium oxide, as well as titanium nitride and tantalum. The experimental results are fitted using a physical simulation model and are analysed for the limiting factors for fast SET kinetics.

  7. SET kinetics of electrochemical metallization cells: influence of counter-electrodes in SiO2/Ag based systems.

    PubMed

    Lübben, M; Menzel, S; Park, S G; Yang, M; Waser, R; Valov, I

    2017-03-01

    The counter-electrode material in resistively switching electrochemical metallization cells (ECMs) is a crucial factor influencing the nucleation of conductive filaments, the equilibrium electrode potentials, and kinetics in the devices, and hence the overall switching characteristics. Here, we demonstrate the influence of the counter-electrode (CE) material on the SET events and the importance of appropriate choice and combination of materials. The counter-electrode material influences the counter-electrode processes at the CE/insulator interface and consequently determines the metal ion concentration in the cells. We measured the switching kinetics for SiO2/Ag based ECM cells using different counter-electrode materials with different electrocatalytic activities towards water reduction, namely platinum, ruthenium, and iridium oxide, as well as titanium nitride and tantalum. The experimental results are fitted using a physical simulation model and are analysed for the limiting factors for fast SET kinetics.

  8. DHA system mediating aerobic and anaerobic dissimilation of glycerol in Klebsiella pneumoniae NCIB 418.

    PubMed Central

    Forage, R G; Lin, E C

    1982-01-01

    In Klebsiella pneumoniae NCIB 418, the pathways normally responsible for aerobic growth on glycerol and sn-glycerol 3-phosphate (the glp system) are superrepressed. However, aerobic growth on glycerol can take place by the intervention of the NAD-linked glycerol dehydrogenase and the ATP-dependent dihydroxyacetone kinase of the dha system normally inducible only anaerobically by glycerol or dihydroxyacetone. Conclusive evidence that the dha system is responsible for both aerobic and anaerobic dissimilation of glycerol was provided by a Tn5 insertion mutant lacking dihydroxyacetone kinase. An enzymatically coupled assay specific for this enzyme was devised. Spontaneous reactivation of the glp system was achieved by selection for aerobic growth on sn-glycerol 3-phosphate or on limiting glycerol as the sole carbon and energy source. However, the expression of this system became constitutive. Aerobic operation of the glp system highly represses synthesis of the dha system enzymes by catabolite repression. Images PMID:6284704

  9. Characterization and optimization of glycerol/sebacate ratio in poly(glycerol-sebacate) elastomer for cell culture application.

    PubMed

    Guo, Xiao-Long; Lu, Xi-Li; Dong, De-Li; Sun, Zhi-Jie

    2014-11-01

    Poly(glycerol-sebacate) (PGS) is an elastomeric biodegradable polyester. Our previous series of studies have showed that PGS has good biocompatibility. In view of the potential use of PGS in bioengineering, we attempt to characterize the PGS polymer with different ratio of glycerol and sebacic acid, and the cell adhesion and growth on these polymers. PGSs with different proportion of glycerol and sebacic acid were synthesized by polycondensation reaction. The microstructure of the series PGSs were characterized by infrared spectroscopy and X-ray diffraction analysis (XRD). Results showed that, with the increase of the ratio of sebacic acid in PGS from 1:0.8, 1:1, to 1:1.2 (ratio of glycerol to sebacic acid), the main diffraction peak in XRD, the sol content and gel swelling increased but then decreased, suggesting that the degree of crosslinking and the inherent degree of order of the series PGS increased and then decreased. With the increase of sebacic acid proportion, water absorption increased and then decreased, and the water absorption ranged from 9.62% to 10.66%. The mass loss of the series of samples in degradation experiments ranged from 24.63% to 40.06% on the 32nd day of degradation. Cell culture data suggested that the polymer with the ratio of 1:0.8 for glycerol and sebacate was suitable for cell adhesion and growth. In conclusion, PGS can be used as the cell culture matrix by modifying the composition ratio of glycerol and sebacic acid to improve the properties of cell adhesion and growth.

  10. Chemical Interactions of Polyethylene Glycols (PEG) and Glycerol with Protein Functional Groups: Applications to PEG, Glycerol Effects on Protein Processes

    PubMed Central

    Knowles, DB; Shkel, Irina A; Phan, Noel M; Sternke, Matt; Lingeman, Emily; Cheng, Xian; Cheng, Lixue; O’Connor, Kevin; Record, M. Thomas

    2015-01-01

    Here we obtain the data needed to predict chemical interactions of polyethylene glycols (PEGs) and glycerol with proteins and related organic compounds, and thereby interpret or predict chemical effects of PEGs on protein processes. To accomplish this we determine interactions of glycerol and tetraEG with >30 model compounds displaying the major C, N, and O functional groups of proteins. Analysis of these data yields coefficients (α-values) quantifying interactions of glycerol, tetraEG and PEG end (-CH2OH) and interior (-CH2OCH2-) groups with these groups, relative to interactions with water. TetraEG (strongly) and glycerol (weakly) interact favorably with aromatic C, amide N, and cationic N, but unfavorably with amide O, carboxylate O and salt ions. Strongly unfavorable O and salt anion interactions help make both small and large PEGs effective protein precipitants. Interactions of tetraEG and PEG interior groups with aliphatic C are quite favorable, while interactions of glycerol and PEG end groups with aliphatic C are not. Hence tetraEG and PEG 300 favor unfolding of the DNA-binding domain of lac repressor (lacDBD) while glycerol, di- and mono-ethylene glycol are stabilizers. Favorable interactions with aromatic and aliphatic C explain why PEG400 greatly increases the solubility of aromatic hydrocarbons and steroids. PEG400-steroid interactions are unusually favorable, presumably because of simultaneous interactions of multiple PEG interior groups with the fused ring system of the steroid. Using α-values reported here, chemical contributions to PEG m-values can be predicted or interpreted in terms of changes in water-accessible surface area (ΔASA), and separated from excluded volume effects. PMID:25962980

  11. Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

    SciTech Connect

    Gupta, S.; Arend, N.; Lunkenheimer, P.; Loidl, A.; Stingaciu, L.; Jalarvo, N.; Mamontov, E.; Ohl, M.

    2015-01-22

    The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is investigated using different neutron scattering techniques. The performed neutron spin echo experiments, which extend up to relatively long relaxation time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectroscopy and light scattering. In conclusion, we show here that the relaxational process causing the excess wing can also be detected by neutron scattering, which directly couples to density fluctuations.

  12. Synthesis of isotopically labeled R- or S-[.sup.13C, .sup.2H] glycerols

    DOEpatents

    Martinez, Rodolfo A.; Unkefer, Clifford J.; Alvarez, Marc A.

    2008-01-22

    The present invention is directed to asymmetric chiral labeled glycerols including at least one chiral atom, from one to two .sup.13C atoms and from zero to four deuterium atoms bonded directly to a carbon atom, e.g., (2S) [1,2-.sup.13C.sub.2]glycerol and (2R) [1,2-.sup.13C.sub.2]glycerol, and to the use of such chiral glycerols in the preparation of labeled amino acids.

  13. Direct measurement of the surface dynamics of supercooled liquid-glycerol by optical scanning a film

    NASA Astrophysics Data System (ADS)

    Zhang, Fang; Zhang, Guo-Feng; Dong, Shuang-Li; Sun, Jian-Hu; Chen, Rui-Yun; Xiao, Lian-Tuan; Jia, Suo-Tang

    2009-09-01

    The surface dynamics of supercooled liquid-glycerol is studied by scanning the thickness of the glycerol film with single photon detection. Measurements are performed at room temperature well above the glycerol's glass transition temperature. It is shown that the surface dynamics of the glycerol film is very sensitive to the temperature. The linear relationship between the thickness of the film and the viscosity predicted by the Vogel-Fulcher-Tammann-Hesse (VFTH) law is also presented experimentally.

  14. Effects of TiO2 coating dosage and operational parameters on a TiO2/Ag photocatalysis system for decolorizing Procion red MX-5B.

    PubMed

    Lin, Yu-Chih; Lee, Ho-Shan

    2010-07-15

    In this study, titanium dioxide (TiO(2)) powder was coated onto the surface of a dendritic silver (Ag) carrier to synthesize TiO(2)/Ag for decolorizing Procion red MX-5B (MX-5B), and related operation factors were also studied. The results showed that even without ultraviolet-A (UVA) irradiation, the Ag carrier from the TiO(2)/Ag catalyst had oxidizing ability, which could effectively degrade MX-5B color, but TiO(2) was ineffective. In addition, TiO(2) from TiO(2)/Ag demonstrated photocatalysis performance when irradiated, and the Ag carrier further showed an electron-scavenging ability to mitigate electron-hole pair recombination, which can improve the photocatalytic efficacy. With the oxidization and electron-scavenging ability of Ag and the photocatalysis ability of TiO(2), TiO(2)/Ag can decolor MX-5B more efficiently than TiO(2). The heavier Ag carrier also improves the solid-liquid separation of nano-TiO(2), making TiO(2)/Ag more suitable for application in slurry systems of photocatalytic water treatment. When the TiO(2)/Ag coating ratio was 50% by weight, there was a sufficient amount of TiO(2) on Ag's surface with a good distribution, and it exhibited a good photocatalysis decolorizing effect. In a study of how operational factors impact the decolorizing of MX-5B in the TiO(2)/Ag photocatalysis system with UVA irradiation (UVA-TiO(2)/Ag), the decolorization efficiency was optimal when the solution was maintained at pH 6.35. The addition of 0.01 M hydrogen peroxide (H(2)O(2)) aided the photocatalysis decolorization efficiency, although excessive H(2)O(2) reacted with hydroxyl free radicals and decreased the active groups in the system, thereby reducing the photocatalysis activity. An operating temperature of 40 degrees C was conducive to MX-5B decolorization, which was better than operating at room temperature.

  15. Plio-Pleistocene Temperature Variability in the Terrestrial Arctic: Insights from Branched Glycerol Dialkyl Glycerol Tetraethers

    NASA Astrophysics Data System (ADS)

    Castañeda, I. S.; Salacup, J.; de Wet, G.; Habicht, M. H.; Keisling, B. A.; Phu, V.; Johnson, J.; Lukas, S.; Lyons, N.; Brigham-Grette, J.

    2014-12-01

    Drill coring at Lake El'gygytgyn (Far East Russia) in 2009 retrieved a 3.6 Ma long sediment core, which is presently the oldest continuous sedimentary record available from the terrestrial Arctic. This unique Plio-Pleistocene record allows for the response of the Arctic to global climate events under a variety of different boundary conditions to be examined. Here we present results of ongoing organic geochemical analyses of Lake El'gygytgyn sediments focusing on the mid-Pliocene warm period, the Plio-Pleistocene transition, the mid-Brunhes transition, and warm Pleistocene interglacial periods including Marine Isotope Stages (MIS) 5, 9, 11, 19 and 31. Despite the ultra-oligotrophic nature of Lake El'gygytgyn and the generally low sedimentary total organic carbon (TOC) content, we find abundant branched glycerol dialkyl glycerol tetraethers (brGDGTs) throughout the entire record and use the methylation and cyclization indices of branched tetraethers (MBT and CBT, respectively) to reconstruct past temperature (Weijers et al., 2007). We hypothesize that the majority of brGDGTs are produced in the lake during the brief summer period of ice free conditions and that MBT/CBT likely reflects a warm season temperature. Trends noted in the MBT/CBT record are in close agreement with pollen-based temperature estimates throughout the entire core. For example, we note a dramatic ~6°C cooling associated with the mid-Pliocene M2 event and thus far MIS 31 has emerged as the warmest period at Lake El'gygytgyn during the past ~ 1 Ma, corroborating the pollen data. Interestingly, a number of abrupt and relatively short-lived cooling events of 2 to 4°C are noted within several of the particularly warm interglacial periods (e.g. MIS 5e, MIS 11 and MIS 31) and are the subject of ongoing investigation. Overall, application of the MBT/CBT paleothermometer to Lake El'gygytgyn sediments is a highly promising technique for generating a Plio-Pleistocene temperature record from the continental

  16. Production of arabitol from glycerol: strain screening and study of factors affecting production yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glycerol is a major byproduct from biodiesel production, and developing new uses for glycerol is imperative to overall economics and sustainability of the biodiesel industry. With the aim of producing xylitol and/or arabitol as the value-added products from glycerol, 214 yeast strains, many osmotole...

  17. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactylated fatty acid esters of glycerol and... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and... additive is a mixture of esters produced by the lactylation of a product obtained by reacting edible...

  18. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Lactylated fatty acid esters of glycerol and... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and... additive is a mixture of esters produced by the lactylation of a product obtained by reacting edible...

  19. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Lactylated fatty acid esters of glycerol and... CONSUMPTION Multipurpose Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be safely used...

  20. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Lactylated fatty acid esters of glycerol and... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and... additive is a mixture of esters produced by the lactylation of a product obtained by reacting edible...

  1. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Lactylated fatty acid esters of glycerol and... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and... additive is a mixture of esters produced by the lactylation of a product obtained by reacting edible...

  2. Metabolic engineering for high glycerol production by the anaerobic cultures of Saccharomyces cerevisiae.

    PubMed

    Semkiv, Marta V; Dmytruk, Kostyantyn V; Abbas, Charles A; Sibirny, Andriy A

    2017-03-09

    Glycerol is used by the cosmetic, paint, automotive, food, and pharmaceutical industries and for production of explosives. Currently, glycerol is available in commercial quantities as a by-product from biodiesel production, but the purity and the cost of its purification are prohibitive. The industrial production of glycerol by glucose aerobic fermentation using osmotolerant strains of the yeasts Candida sp. and Saccharomyces cerevisiae has been described. A major drawback of the aerobic process is the high cost of production. For this reason, the development of yeast strains that effectively convert glucose to glycerol anaerobically is of great importance. Due to its ability to grow under anaerobic conditions, the yeast S. cerevisiae is an ideal system for the development of this new biotechnological platform. To increase glycerol production and accumulation from glucose, we lowered the expression of TPI1 gene coding for triose phosphate isomerase; overexpressed the fused gene consisting the GPD1 and GPP2 parts coding for glycerol-3-phosphate dehydrogenase and glycerol-3-phosphate phosphatase, respectively; overexpressed the engineered FPS1 gene that codes for aquaglyceroporin; and overexpressed the truncated gene ILV2 that codes for acetolactate synthase. The best constructed strain produced more than 20 g of glycerol/L from glucose under micro-aerobic conditions and 16 g of glycerol/L under anaerobic conditions. The increase in glycerol production led to a drop in ethanol and biomass accumulation.

  3. Preparation, characterization, and properties of 1,2-isopropylidene glycerol carbonate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The utilization of excess glycerol supplies derived from the burgeoning biodiesel industry is of major importance to the oleochemical industry as the economic viability of the biodiesel and oleochemical industries are closely linked to glycerol prices. Carbonate compounds based on glycerol, such as...

  4. Oral Glycerol Solutions as a Deterrent to Dehydration during Heat Exposure.

    DTIC Science & Technology

    1982-01-01

    Glycerol oxidation in the animal organism Acta Physiol. Scand. 7:69-79. Larsen , Jens Anker . 1963. Elimination of glycerol as a measure of the...Following a single pharmacological oral dose the glycerol is distributed throughout 56 to 85% of the body mass (Shafrir and Gorin 1963, Larsen 1963, Holst

  5. The Effect of Glycerol Ingestion on Performance during Simulated Multisport Activity

    ERIC Educational Resources Information Center

    Knight, Christopher; Braakhuis, Andrea; Paton, Carl

    2010-01-01

    Glycerol-induced hyperhydration has been applied to endurance sport with limited success as a performance enhancement strategy. Glycerol has been used as a hyperhydrating agent, because it has been shown to be rapidly absorbed and osmotically active; therefore, the fluid intake with glycerol is distributed throughout the body. Hyperhydration with…

  6. Synthesis, characterization and nanocomposite formation of poly(glycerol succinate-co-maleate) with cellulose nanowhiskers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel biodegradable polymer based on glycerol, succinic anhydride and maleic anhydride, poly(glycerol succinate-co-maleate), poly(GlySAMA), was synthesized by melt polycondensation and tested as a matrix for composites with cellulose nanowhiskers. This glycerol-based polymer is thermally stable as...

  7. Thermal and mechanical properties of glycerol-based polymer films infused with plant cell wall polysaccharides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly(glutaric acid-co-glycerol) films were produced by first synthesizing polymer gels from uncatalyzed polyesterification of glutaric acid to glycerol in toluene. Residual amounts of starting materials in the gel matrices were determined by gas chromatography (GC) to contain 15 percent glycerol and...

  8. Nitrogen-Corrected Apparent Metabolizable Energy Value of Crude Glycerol for Laying Hens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experiment was conducted with laying hens to determine the AMEn value of crude glycerol, a co-product of biodiesel production. Crude glycerol (87% glycerol, 9% water, 0.03% methanol, 1.26% Na, and 3,625 kcal/kg gross energy) was obtained from a commercial biodiesel production facility (Ag Process...

  9. Efficient utilization of crude glycerol as fermentation substrate in the synthesis of poly(3-hydroxybutyrate) biopolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One refined and 2 crude glycerol samples were utilized to produce poly(3-hydroxybutyrate) (PHB) by Pseudomonas oleovorans NRRL B-14682. Fermentation conditions were determined to efficiently utilize glycerol while maintaining PHB yields. A batch culture protocol including 1% glycerol and an aerati...

  10. Mechanisms of protein stabilization and prevention of protein aggregation by glycerol.

    PubMed

    Vagenende, Vincent; Yap, Miranda G S; Trout, Bernhardt L

    2009-11-24

    The stability of proteins in aqueous solution is routinely enhanced by cosolvents such as glycerol. Glycerol is known to shift the native protein ensemble to more compact states. Glycerol also inhibits protein aggregation during the refolding of many proteins. However, mechanistic insight into protein stabilization and prevention of protein aggregation by glycerol is still lacking. In this study, we derive mechanisms of glycerol-induced protein stabilization by combining the thermodynamic framework of preferential interactions with molecular-level insight into solvent-protein interactions gained from molecular simulations. Contrary to the common conception that preferential hydration of proteins in polyol/water mixtures is determined by the molecular size of the polyol and the surface area of the protein, we present evidence that preferential hydration of proteins in glycerol/water mixtures mainly originates from electrostatic interactions that induce orientations of glycerol molecules at the protein surface such that glycerol is further excluded. These interactions shift the native protein toward more compact conformations. Moreover, glycerol preferentially interacts with large patches of contiguous hydrophobicity where glycerol acts as an amphiphilic interface between the hydrophobic surface and the polar solvent. Accordingly, we propose that glycerol prevents protein aggregation by inhibiting protein unfolding and by stabilizing aggregation-prone intermediates through preferential interactions with hydrophobic surface regions that favor amphiphilic interface orientations of glycerol. These mechanisms agree well with experimental data available in the literature, and we discuss the extent to which these mechanisms apply to other cosolvents, including polyols, arginine, and urea.

  11. Dynamical modeling of liver Aquaporin-9 expression and glycerol permeability in hepatic glucose metabolism.

    PubMed

    Gena, Patrizia; Buono, Nicoletta Del; D'Abbicco, Marcello; Mastrodonato, Maria; Berardi, Marco; Svelto, Maria; Lopez, Luciano; Calamita, Giuseppe

    2017-01-01

    Liver is crucial in the homeostasis of glycerol, an important metabolic intermediate. Plasma glycerol is imported by hepatocytes mainly through Aquaporin-9 (AQP9), an aquaglyceroporin channel negatively regulated by insulin in rodents. AQP9 is of critical importance in glycerol metabolism since hepatic glycerol utilization is rate-limited at the hepatocyte membrane permeation step. Glycerol kinase catalyzes the initial step for the conversion of the imported glycerol into glycerol-3-phosphate, a major substrate for de novo synthesis of glucose (gluconeogenesis) and/or triacyglycerols (lipogenesis). A model addressing the glucose-insulin system to describe the hepatic glycerol import and metabolism and the correlation with the glucose homeostasis is lacking so far. Here we consider a system of first-order ordinary differential equations delineating the relevance of hepatocyte AQP9 in liver glycerol permeability. Assuming the hepatic glycerol permeability as depending on the protein levels of AQP9, a mathematical function is designed describing the time course of the involvement of AQP9 in mouse hepatic glycerol metabolism in different nutritional states. The resulting theoretical relationship is derived fitting experimental data obtained with murine models at the fed, fasted or re-fed condition. While providing useful insights into the dynamics of liver AQP9 involvement in male rodent glycerol homeostasis our model may be adapted to the human liver serving as an important module of a whole body-model of the glucose metabolism both in health and metabolic diseases.

  12. Genetically engineered rhamnolipid-producing organism for glycerol utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhamnolipid (RL) is a microbial glycolipid currently developed for industrial use as a biobased surfactant. It also possesses antimicrobial activity that is attractive for applications in sanitizing washes. Glycerol byproduct stream from biodiesel production is a promising low-cost substrate for m...

  13. Optimization process of tribenzoine production as a glycerol derived product

    NASA Astrophysics Data System (ADS)

    Widayat, Abdurrakhman, Rifianto, Y.; Abdullah, Hadiyanto, Samsudin, Asep M.; Annisa, A. N.

    2015-12-01

    Tribenzoin is a derived product from glycerol that can produce from glycerol conversion via esterification process. The product can be used in the food industry, cosmetics industry, polymer industry and also can be used to improve the properties of adhesive materials and water resistance in the ink printer.In the other hand, it advantages is environmentally friendly andrenewable because it is not derived from petroleum. This paper discusses the effect of temperature and catalyst concentration for tribenzoin production. For the responses, yield and product composition were observed. Results showed that the highest yield achieved at optimal variable data processed using Central Composite Design (CCD) which is 63.64 temperature (°C), mole ratio of benzoic acidto glycerol is 3.644:1, and catalyst concentration 6.25% (wt% glycerol). Yield products produced 58.71%. FTIR analysis results showed that the samples contained the results of IR spectra wavelength 1761 cm-1 in the fingerprint region and 3165 cm-1 frequency region group. The existence of these two adjustments that fixed in the area is strong evidence that the compound is tribenzoin.

  14. Toxicity of palmitoyl glycerol to mice: depression of thyroid function

    SciTech Connect

    Trumbo, P.R.; Meuten, D.J.; King, M.W.; Tove, S.B.

    1987-10-01

    Mice given propylthiouracil, a thyroid inhibitor, and fed a diet containing a nontoxic level of rac-1(3)-palmitoyl glycerol showed the hypothermia and mortality expected for a toxic dose, but did not show these signs when linoleate or oleate was added to the diet. Loss of radioiodine from the whole animal and thyroid gland was slower when mice were fed the toxic palmitoyl glycerol diet than when fed the same diet containing 4% safflower oil. However, mice fed the two diets did not differ in the extent of the incorporation of radioiodine, and essentially all was bound to protein in each case. Follicular thyroid cells from mice fed the potentially toxic diet that contained unsaturated fat were normal in appearance. Conversely, cells from mice fed the toxic diet were smaller and more densely stained, showing evidence of glycoprotein inside the cell. These findings show that the thyroid gland is affected by the palmitoyl glycerol diet. However, the thyroid is not the only organ affected, because giving either thyroxine or triiodothyronine had no effect on the toxicity of palmitoyl glycerol.

  15. Crude glycerol combustion: particulate, acrolein, and other volatile organic emissions

    EPA Science Inventory

    Crude glycerol is an abundant by-product of biodiesel production. As volumes of this potential waste grow, there is increasing interest in developing new value added uses. One possible use, as a boiler fuel for process heating, offers added advantages of energy integration and ...

  16. Biocomposites Prepared from Fiber Processing Wastes and Glycerol Polyesters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biocomposites were prepared by the addition of flax fiber processing waste to glycerol and adipic acid mixtures. The processing waste consisted of fiber, cuticle, and shive fragments generated during the commercial cleaning of retted flax bast fibers. These waste materials were added at 1, 3, or 5 w...

  17. Dark fermentative bioconversion of glycerol to hydrogen by Bacillus thuringiensis.

    PubMed

    Kumar, Prasun; Sharma, Rishi; Ray, Subhasree; Mehariya, Sanjeet; Patel, Sanjay K S; Lee, Jung-Kul; Kalia, Vipin C

    2015-04-01

    Biodiesel manufacturing units discharge effluents rich in glycerol. The need is to convert crude glycerol (CG) into useful products such as hydrogen (H2). Under batch culture, Bacillusthuringiensis EGU45 adapted on pure glycerol (PG, 2% v/v) resulted in an H2 yield of 0.646 mol/mol glycerol consumed on minimal media (250 mL) supplemented with 1% ammonium nitrate at 37°C over 4 days. Here, H2 constituted 67% of the total biogas. Under continuous culture, at 2 days of hydraulic retention time, B. thuringiensis immobilized on ligno-cellulosic materials (banana leaves - BL, 10% v/v) resulted in a H2 yield of 0.386 mol/mol PG consumed. On CG, the maximal H2 yield of 0.393 mol/mol feed consumed was recorded. In brief, B. thuringiensis could transform CG, on limited resources - minimal medium with sodium nitrate, by immobilizing them on cheap and easily available biowaste, which makes it a suitable candidate for H2 production on a large scale.

  18. Adaptation to physical training in rats orally supplemented with glycerol.

    PubMed

    Andrade, Eric Francelino; Lobato, Raquel Vieira; de Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Vicente da Costa, Diego; de Oliveira Silva, Víviam; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Rosa, Priscila Vieira; Pereira, Luciano José

    2015-01-01

    We evaluated training adaptation and physical performance parameters in rats orally supplemented with glycerol, glucose, or saline, and submitted to moderate aerobic exercise. Thirty male rats were trained for 6 weeks and administered the supplements during the last 4 weeks of the experiment. Animals were distributed in a completely randomized factorial 2 × 3 design (with or without exercise and 3 substrates). Data were subjected to analysis of variance (ANOVA) and means were compared using the Student-Newmann-Keuls test at 5%. Among the trained animals, none of the substances caused differences in the percentages of protein, fat, or water content in the carcass. Compared with the sedentary animals, the trained animals supplemented with saline and glucose showed a higher protein percentage in the carcass. The relative mass of the heart and adrenal glands was higher in the trained animals. Glycerol improved the protein content in non-trained animals and increased the relative adrenal mass in both groups. Glycerol reduced the variation in levels of lactate and aspartate aminotransferase (AST) during the last exercise session. There was no difference between groups regarding the relative mass of the thymus and gastrocnemius or with the diameter of muscle fibers or the neutrophil-lymphocyte ratio. Supplementation with glycerol was efficient at attenuating variation in AST and lactate levels during exercise.

  19. Apparent digestible energy value of crude glycerol fed to pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The apparent digestible energy of crude glycerol, a co-product of biodiesel production, was determined in two studies conducted at the Iowa State University Swine Nutrition Research Farm, Ames, IA. In the first study, 24 barrows with an average body weight of 11.0 kg were fed 376 g/d of a basal corn...

  20. Performance and carcass characteristics of growing pigs fed crude glycerol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Performance and carcass characteristics of growing pigs fed crude glycerol, a co-product of biodiesel production, were determined in a 138-d feeding trial conducted at the Iowa State University Swine Nutrition Research Farm, Ames, IA. Pigs were weaned at 21d of age and were fed a commercial starter-...

  1. Rainbow smelt: the unusual case of cryoprotection by sustained glycerol production in an aquatic animal.

    PubMed

    Driedzic, William R

    2015-07-01

    Rainbow smelt flourish at -1.8 °C, the freezing point of sea water. An antifreeze protein contributes to freeze point depression but, more importantly, cryoprotection is due to an elevation in osmotic pressure, by the accumulation of glycerol. The lower the water temperature, the higher the plasma glycerol with levels recorded as high as 400 mmol l(-1). Glycerol freely diffuses out in direct relation to the glycerol concentration and fish may lose as much as 15% of their glycerol reserve per day. Glycerol levels decrease from a maximum in February/March while water temperature is still sub-zero. The decrease in glycerol may respond to a photoperiod signal as opposed to initiation which is triggered by low temperature. The initial increase in glycerol level is supported by liver glycogen but high sustained glycerol level is dependent upon dietary carbohydrate and protein. The metabolic pathways leading to glycerol involve flux from glycogen/glucose to the level of dihydroxyacetone phosphate (DHAP) via the initial part of glycolysis and from amino acids via a truncated gluconeogenesis again to the level of DHAP. DHAP in turn is converted to glycerol 3-phosphate (G3P) and then directly to glycerol. The key to directing DHAP to G3P is a highly active glycerol 3-P dehydrogenase. G3P is converted directly to glycerol via G3P phosphatase, the rate-limiting step in the process. The transition to glycerol production is associated with increased activities of enzymes at key loci in the top part of glycogenolysis/glycolysis. Curtailment of the final section of glycolysis may reside at the level of pyruvate oxidation with an inactivation of pyruvate dehydrogenase (PDH) driven by increased levels of PDH kinase. Enzymes associated with amino acid trafficking are elevated as is the pivotal enzyme phosphoenolpyruvate carboxykinase.

  2. Content of plasmatic glycerol and activity of hepatic glycerol kinase in broiler chickens fed diets containing different sources and concentrations of glycerine.

    PubMed

    Bernardino, V M P; Rodrigues, P B; de Paula Naves, L; Rosa, P V; Zangerônimo, M G; Gomide, E M; Saldanha, M M; Alvarenga, R R

    2014-04-01

    The objective of this study was to evaluate the effect of three sources of glycerine (crude glycerine from soya bean oil - CGSO, mixed crude glycerine from frying oil and lard--MCG, and a semipurified glycerine from soya bean oil--SPGSO) in four concentrations in the diet (17.5, 35.0, 52.5 and 70.0 g of each type of glycerine per kg of feed) on the levels of plasmatic glycerol and the activity of the hepatic enzyme glycerol kinase in broilers of 22-35 days old (experiment I) and 33-42 days old (experiment II). The highest (p < 0.05) plasmatic glycerol level was detected in broilers fed diet containing CGSO. Independent of the source, increasing the concentration of glycerine led to a linear increase (p < 0.05) in the plasmatic glycerol concentration. In experiment I, all the diets containing glycerine resulted in increased concentrations of plasmatic glycerol, in relation to the control diet without glycerine. However, in experiment II, only the diet containing 17.5 g of CGSO per kg of feed and the diets formulated with any of the three types of glycerine in the inclusion concentrations of 35, 52.5 and 70 g/kg of feed resulted in higher plasmatic glycerol levels than those observed in the control broilers. The source of glycerine influenced the glycerol kinase activity only in experiment II, where the use of CGSO in the diet increased the enzyme activity. For both experiments, the glycerol kinase activity increased with the inclusion of glycerine in the diet. In conclusion, based on the absence of saturation of the glycerol kinase activity for the three glycerine sources and for both rearing periods evaluated, the broilers can metabolize the glycerol (at the level of the phosphorylation of the glycerol to glycerol-3-phosphate in the liver) present in the glycerine when the diet is supplemented with up to 70 g of glycerine per kg of feed.

  3. Crystallization and transformation of polymorphic forms of trioleoyl glycerol and 1,2-dioleoyl-3-rac-linoleoyl glycerol.

    PubMed

    Bayés-García, Laura; Calvet, Teresa; Cuevas-Diarte, Miquel Àngel; Ueno, Satoru; Sato, Kiyotaka

    2013-08-08

    This study examined the influence of different thermal treatments on the crystallization and transformation of trioleoyl glycerol (OOO) and 1,2-dioleoyl-3-rac-linoleoyl glycerol (OOL). Two triacylglycerol (TAG) samples were cooled at 0.5-15 °C·min(-1) and heated at 2 and 15 °C·min(-1). The polymorphic characteristics of the two TAGs were analyzed in situ using differential scanning calorimetry, Raman spectroscopy, and synchrotron radiation X-ray diffraction. Multiple polymorphic forms were identified in OOO (α, β'2, β'1, β2, and β1) and OOL (α, β'2, and β'1). Larger quantities of more stable forms (e.g., β2 and β1 of OOO and β'1 of OOL) were obtained when the samples were slowly cooled and heated. In contrast, less stable polymorphs were obtained with increased cooling and heating rates. Polymorphic transformations occurred in either solid-state or melt-mediation and were influenced by heating rates. The results were analyzed by considering the activation energies for crystallization and transformation of stable and less stable polymorphic forms in comparison with previous studies on 1,3-dipalmitoyl-2-oleoyl-glycerol and 1, 3-dioleoyl-2-palmitoyl-glycerol.

  4. Bonding, Luminescence, Metallophilicity in Linear Au3 and Au2Ag Chains Stabilized by Rigid Diphosphanyl NHC Ligands.

    PubMed

    Ai, Pengfei; Mauro, Matteo; Gourlaouen, Christophe; Carrara, Serena; De Cola, Luisa; Tobon, Yeny; Giovanella, Umberto; Botta, Chiara; Danopoulos, Andreas A; Braunstein, Pierre

    2016-09-06

    The heterofunctional and rigid ligand N,N'-diphosphanyl-imidazol-2-ylidene (PCNHCP; P = P(t-Bu)2), through its phosphorus and two N-heterocyclic carbene (NHC) donors, stabilizes trinuclear chain complexes, with either Au3 or AgAu2 cores, and dinuclear Au2 complexes. The two oppositely situated PCNHCP (L) ligands that "sandwich" the metal chain can support linear and rigid structures, as found in the known tricationic Au(I) complex [Au3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 (OTf = CF3SO3; [Au3L2](OTf)3; Chem. Commun. 2014, 50, 103-105) now also obtained by transmetalation from [Ag3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Ag3L2](OTf)3), or in the mixed-metal tricationic [Au2Ag(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Au2AgL2](OTf)3). The latter was obtained stepwise by the addition of AgOTf to the digold(I) complex [Au2(μ2-PCNHCP,κP,κCNHC)2](OTf)2 ([Au2L2](OTf)2). The latter contains two dangling P donors and displays fluxional behavior in solution, and the Au···Au separation of 2.8320(6) Å in the solid state is consistent with metallophilic interactions. In the solvento complex [Au3Cl2(tht)(μ3-PCNHCP,κP,κCNHC,κP)](OTf)·MeCN ([Au3Cl2(tht)L](OTf)·MeCN), which contains only one L and one tht ligand (tht = tetrahydrothiophene), the metal chain is bent (148.94(2)°), and the longer Au···Au separation (2.9710(4) Å) is in line with relaxation of the rigidity due to a more "open" structure. Similar features were observed in [Au3Cl2(SMe2)L](OTf)·2MeCN. A detailed study of the emission properties of [Au3L2](OTf)3, [Au3Cl2(tht)L](OTf)·MeCN, [Au2L2](OTf)2, and [Au2AgL2](OTf)3 was performed by means of steady state and time-resolved photophysical techniques. The complex [Au3L2](OTf)3 displays a bright (photoluminescence quantum yield = 80%) and narrow emission band centered at 446 nm with a relatively small Stokes' shift and long-lived excited-state lifetime on the microsecond timescale, both in solution and in the solid state. In line with the very narrow emission

  5. Photochromic and self-cleaning properties of TiO2-AgCl/TiO2-xCu thin film.

    PubMed

    Sangchay, Weerachai; Sikong, Lek; Kooptarnond, Kalayanee

    2013-02-01

    The TiO2-AgCl/TiO2-xCu thin films were prepared by sol-gel method and dip coated on glass slide. The prepared films were synthesized at the temperature of 400 degrees C for 2 h with a heating rate of 10 degrees C/min. The microstructure and properties of synthesized TiO2-AgCl/TiO2-xCu thin films were characterized by X-ray diffraction, scanning electron microscopy, atomic forced microscope and UV-vis diffuse reflectance spectroscopy. Finally, the hydrophilic property was evaluated by means of contact angle of water droplet on the films. The results show all samples have film thickness in range of 400-500 nm and their surfaces are dense and strong with a large surface area according to the image of atomic forced microscope. It can be noted that TiO2-AgCl/TiO2-5Cu thin films exhibit the highest photochromic (or the lowest capability of light transmittance) at 250-400 nm. The TiO2-AgCl/TiO2-xCu thin films can block UV C, UV B and UV A rays and exhibit self-cleaning effect (small contact angle, 3.9 degrees ) under UV irradiation.

  6. Ag(nic)2 (nic = nicotinate): a spin-canted quasi-2D antiferromagnet composed of square-planar S = 1/2 Ag(II) ions.

    PubMed

    Manson, Jamie L; Woods, Toby J; Lapidus, Saul H; Stephens, Peter W; Southerland, Heather I; Zapf, Vivien S; Singleton, John; Goddard, Paul A; Lancaster, Tom; Steele, Andrew J; Blundell, Stephen J

    2012-02-20

    Square-planar S = 1/2 Ag(II) ions in polymeric Ag(nic)(2) are linked by bridging nic monoanions to yield 2D corrugated sheets. Long-range magnetic order occurs below T(N) = 11.8(2) K due to interlayer couplings that are estimated to be about 30 times weaker than the intralayer exchange interaction.

  7. Synthesis of Fe{sub 3}O{sub 4}/SiO{sub 2}/Ag nanoparticles and its application in surface-enhanced Raman scattering

    SciTech Connect

    Lv Baoliang; Xu Yao; Tian Hong; Wu Dong; Sun Yuhan

    2010-12-15

    To obtain a recyclable surface-enhanced Raman scattering (SERS) material, we developed a composite of Fe{sub 3}O{sub 4}/SiO{sub 2}/Ag with core/shell/particles structure. The designed particles were synthesized via an ultrasonic route. The Raman scattering signal of Fe{sub 3}O{sub 4} could be shielded by increasing the thickness of the SiO{sub 2} layer to 60 nm. Dye rhodamine B (RB) was chosen as probe molecule to test the SERS effect of the synthesized Fe{sub 3}O{sub 4}/SiO{sub 2}/Ag particles. On the synthesized Fe{sub 3}O{sub 4}/SiO{sub 2}/Ag particles, the characteristic Raman bands of RB could be observed when the RB solution was diluted to 5 ppm (1x10{sup -5} M). Furthermore, the synthesized particles could keep their efficiency till four cycles. -- Graphical Abstract: Fe{sub 3}O{sub 4}/SiO{sub 2}/Ag particles, a recyclable surface-enhanced Raman scattering (SERS) material, were designed and synthesized via a simple ultrasonic route. Display Omitted

  8. A self-cleaning porous TiO2-Ag core-shell nanocomposite material for surface-enhanced Raman scattering.

    PubMed

    Zou, Xiaoxin; Silva, Rafael; Huang, Xiaoxi; Al-Sharab, Jafar F; Asefa, Tewodros

    2013-01-14

    A porous TiO(2)-Ag core-shell nanocomposite material with a large surface area was synthesized by in situ hydrolyzation of Sn(2+)-grafted titanium glycolate microspheres in the presence of Ag(+) ions. The as-prepared nanocomposite material was shown to serve as an efficient self-cleaning surface-enhanced Raman scattering (SERS) substrate.

  9. Synthesis of magnetically recyclable MnFe2O4@SiO2@Ag nanocatalyst: Its high catalytic performances for azo dyes and nitro compounds reduction

    NASA Astrophysics Data System (ADS)

    Kurtan, U.; Amir, Md.; Yıldız, A.; Baykal, A.

    2016-07-01

    In this study, magnetically recycable MnFe2O4@SiO2@Ag nanocatalyst (MnFe2O4@SiO2@Ag MRCs) has been synthesized through co-precipition and chemical reduction method. XRD analysis confirmed the synthesis of single phase nanoproduct with crystallite size of 10 nm. VSM measurements showed the superparamagnetic property of the product. Catalytic studies showed that MnFe2O4@SiO2@Ag MRC could catalyze the reduction of the various azo compounds like methyl orange (MO), methylene blue (MB), eosin Y (EY), and rhodamine B (RhB) and also aromatic nitro compounds such as 4-nitrophenol (4-NP), 4-nitroaniline (4-NA) and 2-nitroaniline (2-NA). Moreover, the magnetic nanocatalyst showed an excellent reusability properties that remained unchanged after several cycles. Therefore, MnFe2O4@SiO2@Ag is the potential candidate for the application of organic pollutants for wastewater treatment.

  10. Atlantic cod (Gadus morhua) larvae can biosynthesis phospholipid de novo from 2-oleoyl-glycerol and glycerol precursors.

    PubMed

    Li, Keshuai; Olsen, Rolf Erik; Østensen, Mari-Ann; Altin, Dag; Kjørsvik, Elin; Olsen, Yngvar

    2016-02-01

    The dietary requirement of phospholipid (PL) of fish larvae has been suggested to originate in an inefficient ability for de novo biosynthesis of PL based on dietary triacylglycerol (TAG). The main objective of the present study was to investigate whether cod larvae could synthesis PL from sn-2-monoacylglycerol (2-MAG) and glycerol precursors. A tube feeding method was used to deliver equal molar aliquots of 2-oleoyl-[1,2,3-(3)H]glycerol and [U-(14)C] glycerol together with bovine serum albumin (BSA) bound 16:0 (palmitic acid) and 22:6n-3 (docosahexaenoic acid, DHA), with or without choline chloride to the foregut of anesthetized cod larvae and thereafter monitoring the metabolism of these components in the larvae through 4 h following injection. Our results showed that both 2-MAG and glycerol precursors contributed to the de novo synthesis of phosphatidylcholine (PC) and the 2-MAG pathway predominated over the G-3-P (glycerol-3-phosphate) pathway in the synthesis of TAG and PC. The molecular ratio of PC/TAG obtained from the 2-MAG and the G-3-P pathways was 0.44-0.74 and 1.02-2.06 within the first hour of tube feeding, suggesting they might have comparable biosynthesis ability of PC and TAG under the conditions of the present study. Furthermore, supplementation of choline chloride significantly increased PC/TAG ratio (p < 0.05) for both pathways. However, further studies are needed to quantify the enzyme activity involved in the CDP-choline (cytidine diphosphate choline) pathway, and the function of choline either in simulating PC synthesis or TAG catabolism or both needs further investigation.

  11. The evolution of interface microstructure in a ZrO[sub 2]/Ag-Cu-Al-Ti system

    SciTech Connect

    Lee, Youngmin; Yu, Jin )

    1993-08-01

    Among ceramic/metal (C/M) joining technologies, the active filler metal method has been studied extensively due to the simple brazing process and excellent joint strength. Active metal elements, typically Ti, are intentionally added to braze alloys to enhance the formation of reaction products between the ceramic and the braze metal at the C/M interface. In the brazing of Al[sub 2]O[sub 3] with the Ag-Cu-Ti filler metal, reaction products such as [gamma]-TiO, Cu[sub 2](Ti, Al)[sub 4]O, Ti[sub 3](Cu[sub 0.76]Al[sub 0.18]Sn[sub 0.06])[sub 3]O were found, while products such as Ti[sub 5]Si[sub 3] and TiN formed in the brazing of Si[sub 3]N[sub 4]. The presence of reaction layers at the C/M interface influences the interface strength in a complex way. In Cu/Al[sub 2]O[sub 3], Co/Al[sub 2]O[sub 3], Ni/Al[sub 2]O[sub 3], and Cu/diamond systems, maxima of joint strength were observed at some intermediate Ti addition, while the flexural strength decreased substantially with the thickening of the TiO layer in a ZrO[sub 2]/Ag-Cu-Sn-Ti system. Thus, composition of the braze alloy (particularly, the content of the active metal), process conditions such as brazing temperature and time, microstructure and mechanical properties of reaction products at the C/M interfaces, interfacial chemistry, and residual stress are primary factors to be studied in order to understand the strengths of the C/M interfaces systematically. In the present and the following papers, evolutions of interfacial microstructures at various brazing conditions, and corresponding interface strengths are reported, respectively, for a ZrO[sub 2]/Ag-Cu-Al-Ti system.

  12. Glycerol extends lifespan of Brachionus manjavacas (Rotifera) and protects against stressors

    PubMed Central

    Snell, Terry W.; Johnston, Rachel K.

    2014-01-01

    Diet has profound effects on animal longevity and manipulation of nutrient sensing pathways is one of the primary interventions capable of lifespan extension. This often is done through caloric restriction (CR) and a variety of CR mimics have been identified that produce life extending effects without adhering to the rigorous CR dietary regimen. Glycerol is a dietary supplement capable mimicking CR by shifting metabolism away from glycolysis and towards oxidative phosphorylation. Glycerol supplementation has a number of beneficial effects, including lifespan extension, improved stress resistance, and enhanced locomotory and mitochondria activity in older age classes. Using rotifers as a model, we show that supplements of 150–300 mM glycerol produced 40–50% extension of mean lifespan. This effect was produced by raising glycerol concentration only three times higher than its baseline concentration in rotifer tissues. Glycerol supplementation decreased rotifer reliance on glycolysis and reduced the pro-aging effects of glucose. Glycerol also acted as a chemical chaperone, mitigating damage by protein aggregation. Glycerol treatment improved rotifer swimming performance in older age classes and maintained more mitochondrial activity. Glycerol treatment provided increased resistance to starvation, heat, oxidation, and osmotic stress, but not UV stress. When glycerol was co-administered with the hexokinase inhibitor 2-deoxyglucose, the lifespan extending effect of glycerol was enhanced. Co-administration of glycerol with inhibitors like 2- deoxyglucose can lower their efficacious doses, thereby reducing their toxic side effects. PMID:24835191

  13. Glycerol extends lifespan of Brachionus manjavacas (Rotifera) and protects against stressors.

    PubMed

    Snell, Terry W; Johnston, Rachel K

    2014-09-01

    Diet has profound effects on animal longevity and manipulation of nutrient sensing pathways is one of the primary interventions capable of lifespan extension. This often is done through caloric restriction (CR) and a variety of CR mimics have been identified that produce life extending effects without adhering to the rigorous CR dietary regimen. Glycerol is a dietary supplement capable mimicking CR by shifting metabolism away from glycolysis and towards oxidative phosphorylation. Glycerol supplementation has a number of beneficial effects, including lifespan extension, improved stress resistance, and enhanced locomotory and mitochondria activity in older age classes. Using rotifers as a model, we show that supplements of 150-300mM glycerol produced 40-50% extension of mean lifespan. This effect was produced by raising glycerol concentration only three times higher than its baseline concentration in rotifer tissues. Glycerol supplementation decreased rotifer reliance on glycolysis and reduced the pro-aging effects of glucose. Glycerol also acted as a chemical chaperone, mitigating damage by protein aggregation. Glycerol treatment improved rotifer swimming performance in older age classes and maintained more mitochondrial activity. Glycerol treatment provided increased resistance to starvation, heat, oxidation, and osmotic stress, but not UV stress. When glycerol was co-administered with the hexokinase inhibitor 2-deoxyglucose, the lifespan extending effect of glycerol was enhanced. Co-administration of glycerol with inhibitors like 2-deoxyglucose can lower their efficacious doses, thereby reducing their toxic side effects.

  14. Effect of crude glycerol impurities on lipid preparation by Rhodosporidium toruloides yeast 32489.

    PubMed

    Gao, Zhen; Ma, Yingqun; Wang, Qunhui; Zhang, Min; Wang, Juan; Liu, Yu

    2016-10-01

    Crude glycerol (byproduct of biodiesel preparation) was utilised as the carbon source to produce lipid using oleaginous yeast Rhodosporidium toruloides 32489. Under the same conditions, lipid production with crude glycerol was higher than those produced with glucose and pure glycerol. The effects of 4 main impurities in crude glycerol (methyl oleate, sodium oleate, NaCl and methanol) on lipid production were investigated. Compared with utilising pure glycerol, addition of methyl oleate, sodium oleate, and NaCl impurities increased lipid production by 47.0%, 68.0% and 64.0%, respectively, while methanol decreased lipid production by 17.7%. However, when methanol was mixed with other impurities, its inhibition effect was alleviated due to the promoting effect of other impurities. Hence, crude glycerol could be used as a renewable and low-cost carbon source to replace pure glucose or glycerol for lipid preparation.

  15. Glycerol dialkyl glycerol tetraethers preserved in stalagmites: a new continental palaeothermometer

    NASA Astrophysics Data System (ADS)

    Blyth, A. J.; Schouten, S.

    2010-12-01

    The ability to recover reliable temperature records is central to palaeoclimatic research, informing our understanding of the past and our models of the future. However, there is a need for new quantitative terrestrial temperature proxies. Here we present a novel palaeothermometer, combining molecular temperature proxies with the strong dating control and established environmental records provided by stalagmites. The results show good correlations between known and calculated temperatures, suggesting that the approach has considerable potential as a climatic proxy. Glycerol dialkyl glycerol tetraethers (GDGTs) are microbial membrane lipids, which vary in structure with temperature and pH [1]. In the terrestrial realm, the focus is on bacterially derived GDGTs, which have been used to measure terrestrial organic matter input to aquatic deposits via the BIT index [2], and developed into a temperature related index (MBT/CBT) in soils and near-shore marine sediments (MBT/CBT), based upon the degree of branching and cyclicisation of the carbon skeleton [3]. Stalagmites form an ideal archive for terrestrial climate records, as they are stable, can be easily dated, and contain a number of environmental proxies (stable isotopes, trace elements, organic matter etc). Attempts have been made to develop inorganic temperature proxies in stalagmites, most recently using isotopic analysis of fluid inclusions. However, the use of organic temperature proxies in this context is largely unstudied. Thirty-eight stalagmite or stalactite samples from twenty-one sites around the world were analysed for their GDGT content. Calcite samples were cleaned and decalcified with HCl, and lipids extracted into dichloromethane via liquid-liquid extraction. Each extract was then prepared and analysed via HPLC-MS following Weijers et al. [3]. The results show low but usable levels of GDGTs in all but one sample. Peak size measurements were made for all recognised compounds associated with BIT and

  16. Antibacterial properties and human gingival fibroblast cell compatibility of TiO2/Ag compound coatings and ZnO films on titanium-based material.

    PubMed

    Chang, Yin-Yu; Lai, Chih-Ho; Hsu, Jui-Ting; Tang, Chih-Hsin; Liao, Wan-Chuen; Huang, Heng-Li

    2012-02-01

    Titanium (Ti)-based materials are widely used in biomedical implant components and are applied successfully in various types of bone-anchored reconstructions. However, in dental implants the Ti materials contact not only bone but also gingival tissues, and are partially exposed to the oral cavity that includes bacteria. This study used titania and silver (TiO(2)/Ag) compound coatings and zinc oxide (ZnO) films to enhance the antibacterial activity of the Ti-based implant. The hydrophobicity of each sample was examined by measuring the contact angle. Streptococcus mutans and human gingival fibroblast (HGF) was cultured on the coated samples, and the antibacterial effects and cell compatibility were determined using a Syto9 fluorescence staining and MTT methods. For the TiO(2)/Ag samples, depositing Ag on the plate at a higher power (which increased the proportion of Ag) increased the contact angle and the hydrophobicity. The bacterial count was lowest for the 50 W TiO(2)/Ag sample, which contained 5.9% Ag. The contact angles of the ZnO samples did not show the same tendency. The antibacterial effect was higher on ZnO-coated samples since bacterial count was threefold lower on ZnO samples as compared to control samples (Ti plate). From the MTT assay test, the mean optical density values for TiO(2)/Ag-coated samples after 72 h of HGF adhesion were similar to the value obtained from the uncoated Ti. However, biocompatibility was lower on ZnO films than in control samples. Conclusively, the antibacterial activity was higher but the cell compatibility was lower on ZnO films than on TiO(2)/Ag coatings.

  17. sn-Glycerol-3-phosphate transport in Salmonella typhimurium.

    PubMed Central

    Hengge, R; Larson, T J; Boos, W

    1983-01-01

    Salmonella typhimurium contains a transport system for sn-glycerol-3-phosphate that is inducible by growth on glycerol and sn-glycerol-3-phosphate. In fully induced cells, the system exhibited an apparent Km of 50 microM and a Vmax of 2.2 nmol/min . 10(8) cells. The corresponding system in Escherichia coli exhibits, under comparable conditions, a Km of 14 microM and a Vmax of 2.2 nmol/min . 10(8) cells. Transport-defective mutants were isolated by selecting for resistance against the antibiotic fosfomycin. They mapped in glpT at 47 min in the S. typhimurium linkage map, 37% cotransducible with gyrA. In addition to the glpT-dependent system, S. typhimurium LT2 contains, like E. coli, a second, ugp-dependent transport system for sn-glycerol-3-phosphate that was derepressed by phosphate starvation. A S. typhimurium DNA bank containing EcoRI restriction fragments in phage lambda gt7 was used to clone the glpT gene in E. coli. Lysogens that were fully active in the transport of sn-glycerol-3-phosphate with a Km of 33 microM and a Vmax of 2.0 nmol/min . 10(8) cells were isolated in a delta glpT mutant of E. coli. The EcoRI fragment harboring glpT was 3.5 kilobases long and carried only part of glpQ, a gene distal to glpT but on the same operon. The fragment was subcloned in multicopy plasmid pACYC184. Strains carrying this hybrid plasmid produced large amounts of cytoplasmic membrane protein with an apparent molecular weight of 33,000, which was identified as the sn-glycerol-3-phosphate permease. Its properties were similar to the corresponding E. coli permease. The presence of the multicopy glpT hybrid plasmid had a strong influence on the synthesis or assembly of other cell envelope proteins of E. coli. For instance, the periplasmic ribose-binding protein was nearly absent. On the other hand, the quantity of an unidentified E. coli outer membrane protein usually present only in small amounts increased. Images PMID:6408060

  18. Glycerol carbonate as green solvent for pretreatment of sugarcane bagasse

    PubMed Central

    2013-01-01

    Background Pretreatment of lignocellulosic biomass is a prerequisite for effective saccharification to produce fermentable sugars. In this study, “green” solvent systems based on acidified mixtures of glycerol carbonate (GC) and glycerol were used to treat sugarcane bagasse and the roles of each solvent in deconstructing biomass were determined. Results Pretreatment of sugarcane bagasse at 90°C for only 30 min with acidified GC produced a solid residue having a glucan digestibility of 90% and a glucose yield of 80%, which were significantly higher than a glucan digestibility of 16% and a glucose yield of 15% obtained for bagasse pretreated with acidified ethylene carbonate (EC). Biomass compositional analyses showed that GC pretreatment removed more lignin than EC pretreatment (84% vs 54%). Scanning electron microscopy (SEM) showed that fluffy and size-reduced fibres were produced from GC pretreatment whereas EC pretreatment produced compact particles of reduced size. The maximal glucan digestibility and glucose yield of GC/glycerol systems were about 7% lower than those of EC/ethylene glycol (EG) systems. Replacing up to 50 wt% of GC with glycerol did not negatively affect glucan digestibility and glucose yield. The results from pretreatment of microcrystalline cellulose (MCC) showed that (1) pretreatment with acidified alkylene glycol (AG) alone increased enzymatic digestibility compared to pretreatments with acidified alkylene carbonate (AC) alone and acidified mixtures of AC and AG, (2) pretreatment with acidified GC alone slightly increased, but with acidified EC alone significantly decreased, enzymatic digestibility compared to untreated MCC, and (3) there was a good positive linear correlation of enzymatic digestibility of treated and untreated MCC samples with congo red (CR) adsorption capacity. Conclusions Acidified GC alone was a more effective solvent for pretreatment of sugarcane bagasse than acidified EC alone. The higher glucose yield obtained

  19. A moderate diet restriction during pregnancy alters the levels of endocannabinoids and endocannabinoid-related lipids in the hypothalamus, hippocampus and olfactory bulb of rat offspring in a sex-specific manner.

    PubMed

    Ramírez-López, María Teresa; Vázquez, Mariam; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosario Noemi; Alén, Francisco; Antón, María; Decara, Juan; Arco, Rocío; Orio, Laura; Suárez, Juan; Lutz, Beat; Gómez de Heras, Raquel; Bindila, Laura; Rodríguez de Fonseca, Fernando

    2017-01-01

    Undernutrition during pregnancy has been associated to increased vulnerability to develop metabolic and behavior alterations later in life. The endocannabinoid system might play an important role in these processes. Therefore, we investigated the effects of a moderate maternal calorie-restricted diet on the levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG), arachidonic acid (AA) and the N-acylethanolamines (NAEs) anandamide (AEA), oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) in the brain of newborn rat offspring. We focused on brain structures involved in metabolism, feeding behavior, as well as emotional and cognitive responses. Female Wistar rats were assigned during the entire pregnancy to either control diet (C) or restriction diet (R), consisting of a 20% calorie-restricted diet. Weight gain and caloric intake of rat dams were monitored and birth outcomes were assessed. 2-AG, AA and NAE levels were measured in hypothalamus, hippocampus and olfactory bulb of the offspring. R dams displayed lower gain weight from the middle pregnancy and consumed less calories during the entire pregnancy. Offspring from R dams were underweight at birth, but litter size was unaffected. In hypothalamus, R male offspring displayed decreased levels of AA and OEA, with no change in the levels of the endocannabinoids 2-AG and AEA. R female exhibited decreased 2-AG and PEA levels. The opposite was found in the hippocampus, where R male displayed increased 2-AG and AA levels, and R female exhibited elevated levels of AEA, AA and PEA. In the olfactory bulb, only R female presented decreased levels of AEA, AA and PEA. Therefore, a moderate diet restriction during the entire pregnancy alters differentially the endocannabinoids and/or endocannabinoid-related lipids in hypothalamus and hippocampus of the underweight offspring, similarly in both sexes, whereas sex-specific alterations occur in the olfactory bulb. Consequently, endocannabinoid and endocannabinoid

  20. A moderate diet restriction during pregnancy alters the levels of endocannabinoids and endocannabinoid-related lipids in the hypothalamus, hippocampus and olfactory bulb of rat offspring in a sex-specific manner

    PubMed Central

    Ramírez-López, María Teresa; Vázquez, Mariam; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosario Noemi; Alén, Francisco; Antón, María; Decara, Juan; Arco, Rocío; Orio, Laura; Suárez, Juan; Lutz, Beat; Gómez de Heras, Raquel; Bindila, Laura

    2017-01-01

    Undernutrition during pregnancy has been associated to increased vulnerability to develop metabolic and behavior alterations later in life. The endocannabinoid system might play an important role in these processes. Therefore, we investigated the effects of a moderate maternal calorie-restricted diet on the levels of the endocannabinoid 2-arachidonoyl glycerol (2-AG), arachidonic acid (AA) and the N-acylethanolamines (NAEs) anandamide (AEA), oleoylethanolamide (OEA) and palmitoylethanolamide (PEA) in the brain of newborn rat offspring. We focused on brain structures involved in metabolism, feeding behavior, as well as emotional and cognitive responses. Female Wistar rats were assigned during the entire pregnancy to either control diet (C) or restriction diet (R), consisting of a 20% calorie-restricted diet. Weight gain and caloric intake of rat dams were monitored and birth outcomes were assessed. 2-AG, AA and NAE levels were measured in hypothalamus, hippocampus and olfactory bulb of the offspring. R dams displayed lower gain weight from the middle pregnancy and consumed less calories during the entire pregnancy. Offspring from R dams were underweight at birth, but litter size was unaffected. In hypothalamus, R male offspring displayed decreased levels of AA and OEA, with no change in the levels of the endocannabinoids 2-AG and AEA. R female exhibited decreased 2-AG and PEA levels. The opposite was found in the hippocampus, where R male displayed increased 2-AG and AA levels, and R female exhibited elevated levels of AEA, AA and PEA. In the olfactory bulb, only R female presented decreased levels of AEA, AA and PEA. Therefore, a moderate diet restriction during the entire pregnancy alters differentially the endocannabinoids and/or endocannabinoid-related lipids in hypothalamus and hippocampus of the underweight offspring, similarly in both sexes, whereas sex-specific alterations occur in the olfactory bulb. Consequently, endocannabinoid and endocannabinoid

  1. Bonding and Anti-bonding Modes of Plasmon Coupling Effects in TiO2-Ag Core-shell Dimers

    PubMed Central

    Li, Quanshui; Zhang, Zhili

    2016-01-01

    Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. First, splitting phenomena of the coupled anti-bonding modes are observed under the longitudinal polarization when the distance between the monomers decreases to a certain level. Second, one of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redshift behaviors as the coupled dipole bonding modes in the same situations. Furthermore, the intensities of those anti-bonding modes weaken with decreasing distance between the monomers, because of the interaction of the induced dipole moment in the monomers and the charge distribution variation on the facing surfaces of the gap by the coulomb attraction. Other split bands are the higher-order mode (octupole-like or triakontadipole-like), which do not have obvious peak-shift behavior, and the intensities have very little attenuation with decreasing distance. Finally, the coupling of the bonding and anti-bonding modes under the longitudinal polarization is symmetric (bonding). PMID:26763719

  2. Synthesis and Overall Photophysical Characterization of SiO2:(Ag/SiO2) Nanostructured Sonogel Hybrid Glasses

    NASA Astrophysics Data System (ADS)

    Morales-Saavedra, Omar G.; Zanella, Rodolfo

    2014-08-01

    Bulk SiO2-based inorganic-inorganic sonogel (SG) hybrid glasses were fabricated with Ag/SiO2 supported metal nanoparticles (MNPs). The catalyst-free SG route was implemented to produce these optically active nanostructured composites by doping the liquid sol-phase with Ag/SiO2 synthesized according to the deposition-precipitation method. As prepared Ag/SiO2-MNPs exhibited particle diameters below 10 nm and homogeneous size distribution. The easy and homogeneous Ag/SiO2 loading within the micro/mesoporous SiO2-SG network has evidenced the guest-host chemical affinity of these systems. This fact allowed us to fabricate outstanding chemically, photo-physically and mechanically stable bulk hybrid monoliths with controllable geometry and doping rates, suitable for linear and nonlinear optical (NLO)-spectroscopic characterizations. Indeed, the hosting SG matrix provided an elevated thermal and mechanical stability protecting the reactive Ag nanoparticles from environment conditions, diminishing their tendency to from aggregates and, above all, preserving their pristine photophysical properties. Comprehensive morphological, structural, spectroscopic and NLO characterizations were performed on the obtained SiO2:(Ag/SiO2) hybrid composites. Results have shown that the nanocrystalline (NC) properties, multipolar nature and small sizes of the implemented Ag/SiO2-nanoparticles, together with the bulk guest-host mechanical interactions, play a crucial role for the observation of outstanding spectroscopic and quadratic NLO properties of the developed hybrid systems.

  3. Bonding and Anti-bonding Modes of Plasmon Coupling Effects in TiO2-Ag Core-shell Dimers

    NASA Astrophysics Data System (ADS)

    Li, Quanshui; Zhang, Zhili

    2016-01-01

    Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. First, splitting phenomena of the coupled anti-bonding modes are observed under the longitudinal polarization when the distance between the monomers decreases to a certain level. Second, one of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redshift behaviors as the coupled dipole bonding modes in the same situations. Furthermore, the intensities of those anti-bonding modes weaken with decreasing distance between the monomers, because of the interaction of the induced dipole moment in the monomers and the charge distribution variation on the facing surfaces of the gap by the coulomb attraction. Other split bands are the higher-order mode (octupole-like or triakontadipole-like), which do not have obvious peak-shift behavior, and the intensities have very little attenuation with decreasing distance. Finally, the coupling of the bonding and anti-bonding modes under the longitudinal polarization is symmetric (bonding).

  4. Bonding and Anti-bonding Modes of Plasmon Coupling Effects in TiO2-Ag Core-shell Dimers.

    PubMed

    Li, Quanshui; Zhang, Zhili

    2016-01-14

    Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. First, splitting phenomena of the coupled anti-bonding modes are observed under the longitudinal polarization when the distance between the monomers decreases to a certain level. Second, one of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redshift behaviors as the coupled dipole bonding modes in the same situations. Furthermore, the intensities of those anti-bonding modes weaken with decreasing distance between the monomers, because of the interaction of the induced dipole moment in the monomers and the charge distribution variation on the facing surfaces of the gap by the coulomb attraction. Other split bands are the higher-order mode (octupole-like or triakontadipole-like), which do not have obvious peak-shift behavior, and the intensities have very little attenuation with decreasing distance. Finally, the coupling of the bonding and anti-bonding modes under the longitudinal polarization is symmetric (bonding).

  5. Structural analysis of TiO2 and TiO2-Ag thin films and their antibacterial behaviors

    NASA Astrophysics Data System (ADS)

    Hsieh, J. H.; Yu, R. B.; Chang, Y. K.; Li, C.

    2012-01-01

    TiO2 (rutile and anatase) thin films was first prepared using reactive sputtering, in an Ar+O2 plasma. In the 2nd stage of the experiment, various amounts (3, 7, and 10 at. %) of Ag was doped into the rutile film in order to form TiO2-Ag thin films. These films were annealed for one hour in Ar atmosphere, at 300, 400, and 500 °C. The films' structures were then examined using X-ray diffractometry. FESEM (field-emission scaning electron microscopy) was used to investigate the surface emergence of Ag particles. As for the examination of optical band gaps and absorption of these films, UV-Vis-NIR photometer was used. The results show that, in as-deposited condition, the addition of Ag might disrupt the growth of crystalline structure and cause the formation of amorphous films. After annealing, it is found that the structure tends to become anatase phase which is a metastable phase between amorphous titanium oxide and rutile. More importantly, the absorption of the Ag-doped films would be enhanced in the visible-light range. Some of the enhancement is clearly due to plasmon resonance effect. The Ag-doped samples have shown some antibacterial effect in dark. When irradiated with light, the samples show a synergistic behavior combining the bactericidal effect of Ag ions and photocatalytic effect of TiO2.

  6. Tunable visible emission of TM-doped ZnS quantum dots (TM: Mn2+, Co2+, Ag+)

    NASA Astrophysics Data System (ADS)

    Taheri Otaqsara, S. M.

    2012-07-01

    3 d transition-metallic ions doped ZnS quantum dots (Q-dots) were synthesized by the facile wet-chemical process. During synthesis, various ions, i.e. manganese (Mn2+), cobalt (Co2+) and silver (Ag+), were used and their photoluminescence (PL) response investigated. UV-vis absorption studies show that the various dopant ions can effectively tune energy band structure. The PL emission band is red shifted on Mn2+ doping (~575 nm) as compared to pure ZnS Q-dots (~420 nm) which is due to 4T1(G) → 6A1(S) radiative transitions. Blue/green-emission peaks at ~487 nm/~508 nm observed, respectively, on Co2+/Ag+ doping are probably arising from the recombination between the sulfur vacancy level and the new dopant level. Luminescence emission efficiency (LEE) is found to be maximum at 5 mol% Mn2+ doping and then decreases. On doping by Ag+ the LEE is found to be maximum at 2 mol% doping and almost completely quenched at 5 mol% doping. Contrary to the above, Co2+ quenched the overall PL.

  7. Electronic packing frustration in complex intermetallic structures: the role of chemical pressure in Ca2Ag7.

    PubMed

    Fredrickson, Daniel C

    2011-07-06

    The assignment of distinct roles to electronics and sterics has a long history in our rationalization of chemical phenomena. Exploratory synthesis in the field of intermetallic compounds challenges this dichotomy with a growing list of phases whose structural chemistry points to an interplay between atomic size effects and orbital interactions. In this paper, we begin with a simple model for how this interdependence may arise in the dense atomic packing of intermetallics: correlations between interatomic distances lead to the inability of a phase to optimize bonds without simultaneously shortening electronically under-supported contacts, a conflict we term electronic packing frustration (EPF). An anticipated consequence of this frustration is the emergence of chemical pressures (CPs) acting on the affected atoms. We develop a theoretical method based on DFT-calibrated μ(2)-Hückel calculations for probing these CP effects. Applying this method to the Ca(2)Ag(7) structure, a variant of the CaCu(5) type with defect planes, reveals its formation is EPF-driven. The defect planes resolve severe CPs surrounding the Ca atoms in a hypothetical CaCu(5)-type CaAg(5) phase. CP analysis also points to a rationale for these results in terms of a CP analogue of the pressure-distance paradox and predicts that the impetus for defect plane insertion is tunable via variations in the electron count.

  8. Modified silica-based heterogeneous catalysts for etherification of glycerol

    NASA Astrophysics Data System (ADS)

    Gholami, Zahra; Abdullah, Ahmad Zuhairi; Gholami, Fatemeh; Vakili, Mohammadtaghi

    2015-07-01

    The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca1.6La0.6/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

  9. Biomass Pretreatment using Ionic Liquid and Glycerol Mixtures

    NASA Astrophysics Data System (ADS)

    Lynam, Joan Goerss

    Lignocellulosic biomass is a renewable, sustainable resource that can replace or supplement fossil fuels use for liquid fuels and chemicals. However, its recalcitrant structure including interwoven cellulose, hemicelluloses, and lignin biomacromolecules is challenging to deconstruct. Pretreating biomass so that it can be converted to useful liquids dominates process economics. Many pretreatment methods exist, but most require hazardous chemicals or processing conditions. Many ionic liquids (ILs), salts molten below 100°C, can be used to deconstruct lignocellulosic biomass and are less hazardous than the volatile organic compounds typically used. While effective, relatively safe, and recyclable, ILs are expensive. To reduce costs, dilution with other safe compounds is desirable, if there is no impact on deconstruction efficiency. Glycerol, a food additive, is inexpensive and becoming even more so since it is a by-product of the burgeoning biodiesel industry. Use of glycerol as an additive or diluent for ILs is extensively evaluated in this work. Rice hulls are an abundant biomass, with over 100 million tons produced per year, but with little practical use. The IL 1-ethyl-3-methylimidazolium formate ([C2mim][O2CH] or EMIM Form) when mixed with an equal amount of glycerol has been shown to be effective in pretreating rice hulls. Ambient pressure, a pretreatment temperature of 110°C, and a reaction time of three hours produced rice hulls that could be enzymatically hydrolyzed to give reasonably good glucose and xylose yields considering the recalcitrance of this silica-armored biomass. The IL [C2mim][O2CH] was also effective when mixed with an equal amount of glycerol to pretreat loblolly pine, a fast-growing softwood. Loblolly pine was pretreated at 140°C for three hours to produce a solid rich in cellulose and hemicelluloses, while a lignin-rich product could be precipitated from the IL. Similar products were obtained from pretreatment with a mixture of 75% 1

  10. The effect of glycerol treatment on crab muscle fibres.

    PubMed

    Papir, D

    1973-04-01

    1. Membrane constants of the closer muscle of the ghost crab, Ocypoda cursor, were determined before and after treatment in hypertonic glycerol solution and return to an artificial sea-water (A.S.W.) solution.2. Muscle contraction was abolished after return of the muscle to A.S.W.3. The membrane capacitance was reduced from 29.0 muF/cm(2) to 10.5 muF/cm(2).4. Other passive properties of the muscle membrane, not dependent on capacitance, were not changed.5. The presynaptic nerve, transmitter release, post-synaptic sensitivity to transmitter and ionic mechanisms of synaptic action were unaffected by glycerol treatment.6. More than 60% of the membrane capacitance/unit area is contributed by the complex tubular system.7. The tubular system in crustacea is necessary for excitation-contraction coupling.

  11. Influence of heat shock on glycerol production in alcohol fermentation.

    PubMed

    Berovic, Marin; Pivec, Aleksandra; Kosmerl, Tatjana; Wondra, Mojmir; Celan, Stefan

    2007-02-01

    The influence of single and double heat shocks induced during the exponential growth phase of the Saccharomyces cerevisiae fermentation of cultivar Sauvignon Blanc grape must was examined. Rapid temperature changes from 18 degrees C to 34 degrees C have been applied. The effect of the duration of exposure to a high temperature has been analyzed. By the applications of a single heat shock and a double heat shock, up to 8.2 g l(-1) and 11.0 g l(-1) glycerol have been produced, respectively. To prevent the evaporation of fine wine bouquet compounds during the temperature changes, reflux coolers on the top of bioreactors have been employed. By using this method, glycerol production was increased by up to 65%.

  12. Modified silica-based heterogeneous catalysts for etherification of glycerol

    SciTech Connect

    Gholami, Zahra; Abdullah, Ahmad Zuhairi Gholami, Fatemeh; Vakili, Mohammadtaghi

    2015-07-22

    The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca{sub 1.6}La{sub 0.6}/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

  13. Controllable superlubricity of glycerol solution via environment humidity.

    PubMed

    Chen, Zhe; Liu, Yuhong; Zhang, Shaohua; Luo, Jianbin

    2013-09-24

    The effect of humidity on the lubrication property of glycerol solution between steel surfaces has been investigated in this paper. A stable superlubricity with a friction coefficient about 0.006 has been found under the relative humidity between around 40% RH and 50% RH. Especially, it is noted that the lubrication state can be switched between superlubricity and nonsuperlubricity by adjusting humidity, which is attributed to the humidity-dependent hydrogen-bonding pattern in the solution. The mechanism of such superlubricity is attributed to the hydrated layer of water between the surface layers, which is formed by hydrogen-bonded glycerol and water molecules and strong enough to bear load, absorbed on each side of the solid surfaces. The work has potential applications, providing a simple and environment-friendly way to accomplish controllable superlubrication between steel pairs, which are commonly used in industry.

  14. Adjuvant properties of a simplified C32 monomycolyl glycerol analogue.

    PubMed

    Bhowruth, Veemal; Minnikin, David E; Agger, Else Marie; Andersen, Peter; Bramwell, Vincent W; Perrie, Yvonne; Besra, Gurdyal S

    2009-04-01

    A simplified C(32) monomycolyl glycerol (MMG) analogue demonstrated enhanced immunostimulatory activity in a dioctadecyl ammonium bromide (DDA)/Ag85B-ESAT-6 formulation. Elevated levels of IFN-gamma and IL-6 were produced in spleen cells from mice immunised with a C(32) MMG analogue comparable activity to the potent Th1 adjuvant, trehalose 6,6'-di-behenate (TDB).

  15. Selective oxidation of glycerol under acidic conditions using gold catalysts

    SciTech Connect

    Villa, Alberto; Veith, Gabriel M; Prati, Laura

    2010-01-01

    H-mordenite-supported PtAu nanoparticles are highly active and selective in the oxidation of glycerol under acidic conditions, which allows the direct preparation of free acids (see picture). The high selectivity for C{sub 3} compounds results from the negligible formation of H{sub 2}O{sub 2}, in contrast to PtAu nanoparticles supported on activated carbon.

  16. Metabolic Flexibility of Yarrowia lipolytica Growing on Glycerol

    PubMed Central

    Egermeier, Michael; Russmayer, Hannes; Sauer, Michael; Marx, Hans

    2017-01-01

    The yeast Yarrowia lipolytica is a fascinating microorganism with an amazing metabolic flexibility. This yeast grows very well on a wide variety of carbon sources from alkanes over lipids, to sugars and glycerol. Y. lipolytica accumulates a wide array of industrially relevant metabolites. It is very tolerant to many environmental factors, above all the pH value. It grows perfectly well over a wide pH range, but it has been described, that the pH has a decisive influence on the metabolite pattern accumulated by this yeast. Here, we set out to characterize the metabolism of different Y. lipolytica strains, isolated from various environments, growing on glycerol at different pH values. The conditions applied for strain characterization are of utmost importance. Shake flask cultures lead to very different results, when compared to controlled conditions in bioreactors regarding pH and aeration. Only one of the tested strains was able to accumulate high amounts of citric acid in shake flask experiments, whereas a group of six strains turned out to accumulate citric acid efficiently under controlled conditions. The present study shows that strains isolated from dairy products predominantly accumulate sugar alcohols at any given pH, when grown on glycerol under nitrogen-limitation. PMID:28174563

  17. Cryocrystallography in capillaries: critical glycerol concentrations and cooling rates

    PubMed Central

    Warkentin, Matthew; Stanislavskaia, Valentina; Hammes, Katherine; Thorne, Robert E.

    2008-01-01

    Capillary tubes have many advantages over multi-well plates for macromol­ecular crystal growth and handling, including the possibility of in situ structure determination. To obtain complete high-resolution X-ray data sets, cryopreservation protocols must be developed to prevent crystalline ice formation and preserve macromolecular crystal order. The minimum glycerol concentrations required to vitrify aqueous solutions during plunging into liquid nitrogen and liquid propane have been determined for capillary diameters from 3.3 mm to 150 µm. For the smallest diameter, the required glycerol concentrations are 30%(w/v) in nitrogen and 20%(w/v) in propane, corresponding to cooling rates of ∼800 and ∼7000 K s−1, respectively. These concentrations are much larger than are required in current best practice using crystals in loops or on microfabricated mounts. In additon, the relation between the minimum cooling rate for vitrification and glycerol concentration has been estimated; this relation is of fundamental importance in developing rational cryopreservation protocols. PMID:19529833

  18. Glycerol production by anaerobic fermentation of molasses on pilot scale

    SciTech Connect

    Virkar, P.D.; Panesar, M.S.

    1987-04-20

    The use of sodium sulphite as a steering agent for enhancing the yield of glycerol during anaerobic ethanol fermentation is well established. Several studies have been reported in the literature using free as well as immobilized cells of Saccharomyces cerevisiae. In these studies it was observed that a relatively high concentration of sulphite in the fermentation broth, typically 40-100 g/l, was required to obtain a commercially significant yield of glycerol on sugar fermented. However, the dosing of large quantities of sulphite generally resulted in reduced viability of the microorganisms and slow fermentations. The glycerol concentration in the fermented broth was generally observed to be in the range 20-40 g/l. The low productivity coupled with the high cost of sulfite rendered the process commercially unattractive. In order to reduce the sulphite requirement, whilst at the same time increasing the productivity, a modified vacuum fermentation was developed in the laboratories. The process was successfully estabilished on a pilot scale and typical data obtained on scaleup are reported below. 8 references.

  19. Enhanced succinate production from glycerol by engineered Escherichia coli strains.

    PubMed

    Li, Qing; Wu, Hui; Li, Zhimin; Ye, Qin

    2016-10-01

    In this study, an engineered strain Escherichia coli MLB (ldhA(-)pflB(-)) was constructed for production of succinate from glycerol. The succinate yield was 0.37mol/mol in anaerobic culture, however, the growth and glycerol consumption rates were very slow, resulting in a low succinate level. Two-stage fermentation was performed in flasks, and the succinate yield reached 0.93mol/mol, but the succinate titer was still low. Hence, overexpression of malate dehydrogenase, malic enzyme, phosphoenolpyruvate (PEP) carboxylase and PEP carboxykinase (PCK) from E. coli, and pyruvate carboxylase from Corynebacterium glutamicum in MLB was investigated for improving succinate production. Overexpression of PCK resulted in remarkable enhancement of glycerol consumption and succinate production. In flask experiments, the succinate concentration reached 118.1mM, and in a 1.5-L bioreactor the succinate concentration further increased to 360.2mM. The highest succinate yield achieved 0.93mol/mol, which was 93% of the theoretical yield, in the anaerobic stage.

  20. Modulation of glycerol and ethanol yields during alcoholic fermentation in Saccharomyces cerevisiae strains overexpressed or disrupted for GPD1 encoding glycerol 3-phosphate dehydrogenase.

    PubMed

    Michnick, S; Roustan, J L; Remize, F; Barre, P; Dequin, S

    1997-07-01

    The possibility of the diversion of carbon flux from ethanol towards glycerol in Saccharomyces cerevisiae during alcoholic fermentation was investigated. Variations in the glycerol 3-phosphate dehydrogenase (GPDH) level and similar trends for alcohol dehydrogenase (ADH), pyruvate decarboxylase and glycerol-3-phosphatase were found when low and high glycerol-forming wine yeast strains were compared. GPDH is thus a limiting enzyme for glycerol production. Wine yeast strains with modulated GPD1 (encoding one of the two GPDH isoenzymes) expression were constructed and characterized during fermentation on glucose-rich medium. Engineered strains fermented glucose with a strongly modified [glycerol] : [ethanol] ratio. gpd1delta mutants exhibited a 50% decrease in glycerol production and increased ethanol yield. Overexpression of GPD1 on synthetic must (200 g/l glucose) resulted in a substantial increase in glycerol production ( x 4) at the expense of ethanol. Acetaldehyde accumulated through the competitive regeneration of NADH via GPDH. Accumulation of by-products such as pyruvate, acetate, acetoin, 2,3 butane-diol and succinate was observed, with a marked increase in acetoin production.

  1. Lipolysis and glycerol gluconeogenesis in simultaneously fasting and lactating northern elephant seals.

    PubMed

    Houser, Dorian S; Champagne, Cory D; Crocker, Daniel E

    2007-12-01

    Adult female elephant seals (Mirounga angustirostris) combine long-term fasting with lactation and molting. Glycerol gluconeogenesis has been hypothesized as potentially meeting all of the glucose requirements of the seals during these fasts. To test this hypothesis, a primed constant infusion of [2-(14)C]glycerol was administered to 10 ten adult female elephant seals at 5 and 21-22 days postpartum and to 10 additional adult females immediately after the molt. Glycerol kinetics, rates of lipolysis, and the contribution of glycerol to glucose production were determined for each period. Plasma metabolite levels as well as insulin, glucagon, and cortisol were also measured. Glycerol rate of appearance was not significantly correlated with mass (P = 0.14, r2 = 0.33) but was significantly related to the percentage of glucose derived from glycerol (P < 0.01, r2 = 0.81) during late lactation. The contribution of glycerol to glucose production was <3% during each fasting period, suggesting a lower contribution to gluconeogenesis than is observed in other long-term fasting mammals. Because of a high rate of endogenous glucose production in fasting elephant seals, it is likely that glycerol gluconeogenesis still makes a substantial contribution to the substrate needs of glucose-dependent tissues. The lack of a relationship between glucoregulatory hormones and glycerol kinetics, glycerol gluconeogenesis, and metabolites supports the proposition that fasting elephant seals do not conform to the traditional insulin-glucagon model of substrate metabolism.

  2. Regulation of glycerol metabolism in Enterobacter aerogenes NBRC12010 under electrochemical conditions.

    PubMed

    Hatayama, Kouta; Yagishita, Tatsuo

    2009-06-01

    Enterobacter aerogenes NBRC12010 was able to ferment glycerol to ethanol and hydrogen gas. Fermentation of glycerol ceased in the stationary phase of growth, and it was activated by electrochemical reactions using thionine as an electron transfer mediator from bacterial cells to an electrode. Using resting cells of E. aerogenes NBRC12010 in only citrate buffer solution, the cells did not consume glycerol at all, but they could metabolize glucose. These results suggest that the regulation of glycerol metabolism occurred at enzymatic steps before glycolysis. In E. aerogenes NBRC12010, glycerol was metabolized via glycerol dehydrogenase (GDH) and then dehydroxyacetone kinase. The GDH-catalyzed reaction mainly depended on the ratio of NAD(+)/NADH. At a NAD(+)/NADH ratio of nearly 1 or less, it was substantially suppressed and glycerol metabolism stopped. When the ratio was higher than 1, GDH was activated and glycerol was metabolized. Thus, the reaction of glycerol metabolism depended on the balance of cellular NAD(+)/NADH. Exogenous NADH was oxidized to NAD(+) by electrochemical reactions with thionine. We proposed the activation mechanism of glycerol metabolism under electrochemical conditions.

  3. Measurement of serum total glycerides and free glycerol by high-performance liquid chromatography.

    PubMed

    Li, Hongxia; Dong, Jun; Chen, Wenxiang; Wang, Shu; Guo, Hanbang; Man, Yong; Mo, Peisheng; Li, Jianzhai

    2006-09-01

    Serum levels of total glycerides and free glycerol are important indices of lipid metabolism and cardiovascular disease risk. Convenient enzymatic methods of measurement have been available, but they are susceptible to interference. Situations exist in both research and clinical laboratories in which more specific and precise methods are needed. We developed HPLC methods for the measurement of serum total glycerides and free glycerol. For total glycerides, serum was mixed with an internal standard (1,2,4-butanetriol) and treated with alcoholic sodium hydroxide to hydrolyze glycerides to glycerol. After deproteinization with tungstic acid, the glycerol was benzoylated with an optimized Schotten-Baumann reaction and analyzed by HPLC. For free glycerol, serum was equilibrated with the internal standard and deproteinized with tungstic acid to remove the glycerides. The glycerol was benzoylated and analyzed as for total glycerol. Various factors were investigated, and no significant sources of interference were detected. The total coefficients of variation ranged from 0.7% to 2.0% for total glycerides and from 1.7% to 3.2% for free glycerol. The analytical recoveries ranged from 98.5% to 101.6%. In conclusion, simple and reliable HPLC methods for serum total glycerides and free glycerol have been developed. The methods may also be used for the analyses of glycerol or glycerides in other biological samples.

  4. Effect of Glycerol Water Binary Mixtures on the Structure and Dynamics of Protein Solutions

    SciTech Connect

    Ghattyvenkatakrishna, Pavan K; Carri, Gustavo A.

    2014-01-01

    We have performed 20ns of fully atomistic molecular dynamics simulations of Hen Egg-White Lysozyme in 0, 10, 20, 30 and 100% by weight of glycerol in water to better understand the microscopic physics behind the bioprotection offered by glycerol to naturally occuring biological systems. The sovlent exposure of protein surface residues changes when glycerol is introduced. The dynamic behavior of the protein, as quantified by the Incoherent Intermediate Scattering Function, shows a non-monotonic dependence on glycerol content. The fluctuations of the protein residues with respect to each other were found to be similar in all water containing solvents; but different from the pure glycerol case. The increase in the number of protein glycerol hydrogen bonds in glycerol water binary mixtures explains the slowing down of protein dynamics as the glycerol content increases. We also explored the dynamic behavior of the hydration layer. We show that the short-length scale dynamics of this layer are insenstive to glycerol concentration. However, the long-length scale behavior shows a significant dependence on glycerol content. We also provide insights into the behavior of bound and mobile water molecules.

  5. A specific glycerol kinase induces rapid cold hardening of the diamondback moth, Plutella xylostella.

    PubMed

    Park, Youngjin; Kim, Yonggyun

    2014-08-01

    Insects in temperate zones survive low temperatures by migrating or tolerating the cold. The diamondback moth, Plutella xylostella, is a serious insect pest on cabbage and other cruciferous crops worldwide. We showed that P. xylostella became cold-tolerant by expressing rapid cold hardiness (RCH) in response to a brief exposure to moderately low temperature (4°C) for 7h along with glycerol accumulation in hemolymph. Glycerol played a crucial role in the cold-hardening process because exogenously supplying glycerol significantly increased the cold tolerance of P. xylostella larvae without cold acclimation. To determine the genetic factor(s) responsible for RCH and the increase of glycerol, four glycerol kinases (GKs), and glycerol-3-phosphate dehydrogenase (PxGPDH) were predicted from the whole P. xylostella genome and analyzed for their function associated with glycerol biosynthesis. All predicted genes were expressed, but differed in their expression during different developmental stages and in different tissues. Expression of the predicted genes was individually suppressed by RNA interference (RNAi) using double-stranded RNAs specific to target genes. RNAi of PxGPDH expression significantly suppressed RCH and glycerol accumulation. Only PxGK1 among the four GKs was responsible for RCH and glycerol accumulation. Furthermore, PxGK1 expression was significantly enhanced during RCH. These results indicate that a specific GK, the terminal enzyme to produce glycerol, is specifically inducible during RCH to accumulate the main cryoprotectant.

  6. Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures.

    PubMed

    Selembo, Priscilla A; Perez, Joe M; Lloyd, Wallis A; Logan, Bruce E

    2009-12-15

    The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H(2)/mol-glycerol (72 mL-H(2)/g-COD) and 0.69 mol-PD/mol-glycerol. Glucose fermentation using the same mixed cultures produced more hydrogen gas (1.06 mol-H(2)/mol-glucose) but no PD. Changing the source of inoculum affected gas production likely due to prior acclimation of bacteria to this type of substrate. Fermentation of the glycerol produced from biodiesel fuel production (70% glycerol content) produced 0.31 mol-H(2)/mol-glycerol (43 mL H(2)/g-COD) and 0.59 mol-PD/mol-glycerol. These are the highest yields yet reported for both hydrogen and 1,3-propanediol production from pure glycerol and the glycerol byproduct from biodiesel fuel production by fermentation using mixed cultures. These results demonstrate that production of biodiesel can be combined with production of hydrogen and 1,3-propanediol for maximum utilization of resources and minimization of waste.

  7. Research note: investigation on the metabolism of glycerol in the rumen of bulls.

    PubMed

    Kijora, C; Bergner, H; Götz, K P; Bartelt, J; Szakács, J; Sommer, A

    1998-01-01

    Two bulls, each fitted with rumen and duodenal cannulas, received (in addition to a hay-grain diet) twice daily an infusion of 200 g glycerol into the rumen over a period of six days. During this preliminary in vivo investigation, the influence of a glycerol application on the rumen environment over a six-day adaptation period was examined. Samples of rumen fluid were collected daily, two hours after glycerol infusion. An additional 15N-urea application into the rumen was given on days 1 (without glycerol infusion), 3 and 7 (with glycerol infusion). Extra samples of rumen fluid and blood plasma (from puncture of vena jungularis) were taken through the 12th hour following urea application. Rumen fluid pH was reduced due to glycerol intake from 6.3 (day 1, without glycerol) to 5.4 by day 7. Molar proportion of acetic acid to propionic acid decreased from 3.5 (day 1) to 2.1 (days 6 and 7). Average glycerol disappearance rate from the rumen was 4.7 gl-1 h-1 for the first hour. Only small amounts of glycerol could be detected in the duodenal digesta. Blood plasma glycerol content was significantly higher after glycerol application (0.061 mmol l-1 vs. 0.019 mmol l-1). The incorporation of 15N into the rumen bacteria and the proportion of bacterial N (as percent of TCA-precipitable N in the rumen fluid) were lower after glycerol influsion. These results, coupled with the lower concentration of iso-acids (isobutyric and isovaleric acids) in the rumen fluid, indicate that the high amount of glycerol infusion (10% of DMI) reduced protein metabolism of rumen bacteria throughout the experimental period.

  8. Flavor impacts of glycerol in the processing of yeast fermented beverages: a review.

    PubMed

    Zhao, Xiangdong; Procopio, Susanne; Becker, Thomas

    2015-12-01

    Glycerol contributes to the beverage body and fullness. Moreover, it also influences the flavor intensity. As a major byproduct, glycerol not only serves critical roles in yeast osmoregulation and redox balancing, but also acts as the carbon competitor against ethanol in alcoholic fermentation. Therefore, increasing glycerol yield benefits both the flavor and ethanol reduction for the fermented beverages. Glycerol yield has been elevated either by fermentation optimization or by yeast genetic modification. The fermentation optimizations reached maximum 14 g/L glycerol through screening yeast strains and optimizing fermentation parameters. Meanwhile the yeast overexpressing GPD1 (encoding glycerol-3-phosphate dehydrogenase) produced up to 6 folds more glycerol for beer and wine. Except for glycerol improvement, the genetically modified yeasts accumulated dramatically undesirable compounds such as acetaldehyde, acetate and acetoin which are detrimental for beverage flavor. In comparison, the natural high glycerol producers showed strain-specific manner on the yeast-derived aroma compounds like volatile acids, fusel alcohols, esters, and aldehydes. Temperature, sugar concentration, nitrogen composition, oxygen and pH-value, which influence glycerol biosynthesis, also obtained various effects on the production of aromatic compounds. In the current review, we firstly deliberate the organoleptic contributions of glycerol for fermented beverages. Furthermore, glycerol optimization strategies are discussed regarding to the yield improvement, the genes expressions, the overall flavor impacts and the feasibilities in beverage applications. Lastly, for improving beverage flavor by glycerol optimization, a high-throughput platform is proposed to increase the screening capacity of yeast strains and parameters in the processing of fermented beverages.

  9. Possibility of analytical finding of glycerol caused by self-catheterization in doping control.

    PubMed

    Okano, Masato; Nishitani, Yasunori; Kageyama, Shinji

    2014-01-01

    Glycerol is listed on the World Anti-Doping Agency (WADA) prohibited list as a masking agent principally because the administration of glycerol increases plasma volume and decreases the concentration of haemoglobin and the value of haematocrit in blood. Glycerol is a naturally occurring substance; therefore, the threshold is set as 1.0 mg/mL in the WADA technical document (WADA TD2013DL). In a WADA-accredited doping control laboratory, three doping control urine specimens collected from impaired athletes were determined to contain a high concentration of glycerol (>1.0 mg/mL); two of these specimens were considered adverse analytical findings (AAFs). Self-catheterization is necessary for athletes with neurological disorders such as neurogenic bladder dysfunction. We conducted a simple simulation of self-catheterization as an experimental test using urethral catheters with an antiseptic agent containing glycerol to confirm the influence of this antiseptic agent on the quantitative value of glycerol in doping control analysis. Some users employ a catheter with glycerol solution (ca. 1 mL) to avoid pain during use. The urine sample passed through such a catheter exhibited a glycerol concentration (4.94 mg/mL) greater than the threshold level. In September 2014, the threshold for glycerol will change from 1.0 to 4.3 mg/mL (WADA TD2014DL); however, a possibility exists for the quantitative value of glycerol in doping control analysis to exceed the threshold because of the use of an antiseptic agent containing glycerol for self-catheterization. The AAF for glycerol for impaired athletes, particularly those who participate in Paralympic sports, should account for the use of a catheter with glycerol.

  10. Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

    DOE PAGES

    Gupta, S.; Arend, N.; Lunkenheimer, P.; ...

    2015-01-22

    The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is investigated using different neutron scattering techniques. The performed neutron spin echo experiments, which extend up to relatively long relaxation time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectroscopy and light scattering. In conclusion, we show here that the relaxational process causing the excess wing can also be detected by neutron scattering, whichmore » directly couples to density fluctuations.« less

  11. Impact of impurities in biodiesel-derived crude glycerol on the fermentation by Clostridium pasteurianum ATCC 6013.

    PubMed

    Venkataramanan, Keerthi P; Boatman, Judy J; Kurniawan, Yogi; Taconi, Katherine A; Bothun, Geoffrey D; Scholz, Carmen

    2012-02-01

    During the production of biodiesel, crude glycerol is produced as a byproduct at 10% (w/w). Clostridium pasteurianum has the inherent potential to grow on glycerol and produce 1,3-propanediol and butanol as the major products. Growth and product yields on crude glycerol were reported to be slower and lower, respectively, in comparison to the results obtained from pure glycerol. In this study, we analyzed the effect of each impurity present in the biodiesel-derived crude glycerol on the growth and metabolism of glycerol by C. pasteurianum. The crude glycerol contains methanol, salts (in the form of potassium chloride or sulfate), and fatty acids that were not transesterified. Salt and methanol were found to have no negative effects on the growth and metabolism of the bacteria on glycerol. The fatty acid with a higher degree of unsaturation, linoleic acid, was found to have strong inhibitory effect on the utilization of glycerol by the bacteria. The fatty acid with lower or no degrees of unsaturation such as stearic and oleic acid were found to be less detrimental to substrate utilization. The removal of fatty acids from crude glycerol by acid precipitation resulted in a fermentation behavior that is comparable to the one on pure glycerol. These results show that the fatty acids in the crude glycerol have a negative effect by directly affecting the utilization of glycerol as the carbon source, and hence their removal from crude glycerol is an essential step towards the utilization of crude glycerol.

  12. Studies on Freezing RAM Semen in Absence of Glycerol.

    NASA Astrophysics Data System (ADS)

    Abdelnaby, Abdelhady Abdelhakeam

    1988-12-01

    Glycerol is widely used as a major cryoprotective agent for freezing spermatozoa of almost all species. However, it reduces fertility of sheep inseminated cervically compared with intrauterine insemination. Studies were conducted to develop a method and procedure for freezing ram semen in the absence of glycerol. Post -thaw survival of ram spermatozoa frozen in the absence of glycerol was affected by time and temperature after collection and before dilution and time after dilution and before freezing. Increase in time at 5^ circC before or after dilution and before freezing increased both post-thaw motility and number of cells passing through Sephadex filter. A cold dilution method was developed. Slow cooling of fresh ram semen and diluting at 5^circ C 2-3 hr. after collection, then freezing 1 hr. after dilution improved both post-thaw motility and number of cells passing through Sephadex filter compared with immediate dilution at 30-37^circC after collection and freezing 3-4 hr. later (P < 0.05). An extender was developed to freeze ram semen in the absence of glycerol. An increase in post-thaw motility was obtained when semen was extended in TES titrated with Tris to pH 7.0 (TEST) and osmotic pressure of 375-400 mOsm/kg, containing 25-30% (v/v) egg yolk and 10% (v/v) maltose. A special device (boat) for freezing was constructed to insure the same height of the sample above LN _2 and thus the same freezing rate from freeze to freeze. Freezing of semen in 0.25cc straws at 5-10 cm above LN_2 (73.8 to 49.5 ^circC/min) yielded higher post-thaw motility than the rates resulted from freezing at 15 cm above LN_2 or 1 cm above LN _2. Faster Thawing in 37^ circC water for 30 sec. (7.8^ circC/sec.) increased post-thaw motility compared with slower thawing in 5 or 20^circ C water (P < 0.05). A lambing rate of 52.2% was obtained in one fertility trial conducted with ram semen frozen without glycerol and 17.1% in a second trial. One injection (IM) of 15 mg PGF_{2alpha}/ewe for

  13. Thermal Expansion and Second Harmonic Generation Response of the Tungsten Bronze Pb2AgNb5O15.

    PubMed

    Lin, Kun; Gong, Pifu; Sun, Jing; Ma, Hongqiang; Wang, You; You, Li; Deng, Jinxia; Chen, Jun; Lin, Zheshuai; Kato, Kenichi; Wu, Hui; Huang, Qingzhen; Xing, Xianran

    2016-03-21

    The incorporation of transition metal element Ag was performed to explore negative thermal expansion (NTE) materials with tetragonal tungsten bronze (TTB) structures. In this study, the structure and thermal expansion behaviors of a polar TTB oxide, Pb2AgNb5O15 (PAN), were systematically investigated by high-resolution synchrotron powder diffraction, high-resolution neutron powder diffraction, transmission electron microscope (TEM), and high-temperature X-ray diffractions. The TEM and Rietveld refinements revealed that the compound PAN displays (√2a(TTB), √2b(TTB), 2c(TTB))-type superstructure. This superstructure within the a-b plane is caused by the ordering of A-site cations, while the doubling of the c axis is mainly induced by a slight tilt distortion of the NbO6 octahedra. The transition metal Ag has larger spontaneous polarization displacements than Pb, but the Pb-O covalence seems to be weakened compared to the potassium counterpart Pb2KNb5O15 (PKN), which may account for the similar Curie temperature and uniaxial NTE behavior for PAN and PKN. Powder second harmonic generation (SHG) measurement indicates that PAN displays a moderate SHG response of ∼0.2 × LiNbO3 (or ∼100 × α-SiO2) under 1064 nm laser radiation. The magnitudes of the local dipole moments in NbO6 and PbOx polyhedra were quantified using bond-valence approach. We show that the SHG response stems from the superposition of dipole moments of both the PbO(x) and NbO6 polyhedra.

  14. Dielectric and specific heat relaxations in vapor deposited glycerol

    SciTech Connect

    Kasina, A. E-mail: wubbenhorst@fys.kuleuven.be; Putzeys, T.; Wübbenhorst, M. E-mail: wubbenhorst@fys.kuleuven.be

    2015-12-28

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk T{sub g} and subsequent cooling/reheating revealed a step-wise increase in c{sub p} by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at −75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of “MROL glycerol” to its “normal” (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy c{sub p}, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τ{sub cal} from that of normal “bulk” glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the

  15. Over-Expression of Monoacylglycerol Lipase (MGL) in Small Intestine Alters Endocannabinoid Levels and Whole Body Energy Balance, Resulting in Obesity

    PubMed Central

    Chon, Su-Hyoun; Douglass, John D.; Zhou, Yin Xiu; Malik, Nashmia; Dixon, Joseph L.; Brinker, Anita; Quadro, Loredana; Storch, Judith

    2012-01-01

    The function of small intestinal monoacylglycerol lipase (MGL) is unknown. Its expression in this tissue is surprising because one of the primary functions of the small intestine is to convert diet-derived MGs to triacylglycerol (TG), and not to degrade them. To elucidate the function of intestinal MGL, we generated transgenic mice that over-express MGL specifically in small intestine (iMGL mice). After only 3 weeks of high fat feeding, iMGL mice showed an obese phenotype; body weight gain and body fat mass were markedly higher in iMGL mice, along with increased hepatic and plasma TG levels compared to wild type littermates. The iMGL mice were hyperphagic and displayed reduced energy expenditure despite unchanged lean body mass, suggesting that the increased adiposity was due to both increased caloric intake and systemic effects resulting in a hypometabolic rate. The presence of the transgene resulted in lower levels of most MG species in intestinal mucosa, including the endocannabinoid 2-arachidonoyl glycerol (2-AG). The results therefore suggest a role for intestinal MGL, and intestinal 2-AG and perhaps other MG species, in whole body energy balance via regulation of food intake as well as metabolic rate. PMID:22937137

  16. Over-expression of monoacylglycerol lipase (MGL) in small intestine alters endocannabinoid levels and whole body energy balance, resulting in obesity.

    PubMed

    Chon, Su-Hyoun; Douglass, John D; Zhou, Yin Xiu; Malik, Nashmia; Dixon, Joseph L; Brinker, Anita; Quadro, Loredana; Storch, Judith

    2012-01-01

    The function of small intestinal monoacylglycerol lipase (MGL) is unknown. Its expression in this tissue is surprising because one of the primary functions of the small intestine is to convert diet-derived MGs to triacylglycerol (TG), and not to degrade them. To elucidate the function of intestinal MGL, we generated transgenic mice that over-express MGL specifically in small intestine (iMGL mice). After only 3 weeks of high fat feeding, iMGL mice showed an obese phenotype; body weight gain and body fat mass were markedly higher in iMGL mice, along with increased hepatic and plasma TG levels compared to wild type littermates. The iMGL mice were hyperphagic and displayed reduced energy expenditure despite unchanged lean body mass, suggesting that the increased adiposity was due to both increased caloric intake and systemic effects resulting in a hypometabolic rate. The presence of the transgene resulted in lower levels of most MG species in intestinal mucosa, including the endocannabinoid 2-arachidonoyl glycerol (2-AG). The results therefore suggest a role for intestinal MGL, and intestinal 2-AG and perhaps other MG species, in whole body energy balance via regulation of food intake as well as metabolic rate.

  17. Transient Cannabinoid Receptor 2 Blockade during Immunization Heightens Intensity and Breadth of Antigen-specific Antibody Responses in Young and Aged mice

    PubMed Central

    Dotsey, Emmanuel; Ushach, Irina; Pone, Egest; Nakajima, Rie; Jasinskas, Algis; Argueta, Donovan A.; Dillon, Andrea; DiPatrizio, Nicholas; Davies, Huw; Zlotnik, Albert; Crompton, Peter D.; Felgner, Philip L.

    2017-01-01

    The hallmark of vaccines is their ability to prevent the spread of infectious pathogens and thereby serve as invaluable public health tool. Despite their medical relevance, there is a gap in our understanding of the physiological factors that mediate innate and adaptive immune response to vaccines. The endocannabinoid (eCB) system is a critical modulator of homeostasis in vertebrates. Our results indicate that macrophages and dendritic cells produce the endocannabinoid, 2-arachidonoyl-sn-glycerol (2-AG) upon antigen activation. We have also established that 2-AG levels are upregulated in the serum and in the lymph node of mice during vaccination. We hypothesized that the intrinsic release of eCBs from immune cells during activation by pathogenic antigens mitigate inflammation, but also suppress overall innate and adaptive immune response. Here we demonstrate, for the first time, that transient administration of the cannabinoid receptor 2 antagonist AM630 (10 mg/kg) or inverse agonist JTE907 (3 mg/kg) during immunization heightens the intensity and breadth of antigen-specific immune responses in young and aged mice through the upregulation of immunomodulatory genes in secondary lymphoid tissues. PMID:28209996

  18. Engineering an Obligate Photoautotrophic Cyanobacterium to Utilize Glycerol for Growth and Chemical Production.

    PubMed

    Kanno, Masahiro; Atsumi, Shota

    2017-01-20

    Cyanobacteria have attracted much attention as a means to directly recycle carbon dioxide into valuable chemicals that are currently produced from petroleum. However, the titers and productivities achieved are still far below the level required in industry. To make a more industrially applicable production scheme, glycerol, a byproduct of biodiesel production, can be used as an additional carbon source for photomixotrophic chemical production. Glycerol is an ideal candidate due to its availability and low cost. In this study, we found that a heterologous glycerol respiratory pathway enabled Synechococcus elongatus PCC 7942 to utilize extracellular glycerol. The engineered strain produced 761 mg/L of 2,3-butanediol in 48 h with a 290% increase over the control strain under continuous light conditions. Glycerol supplementation also allowed for continuous cell growth and 2,3-butanediol production in diurnal light conditions. These results highlight the potential of glycerol as an additional carbon source for photomixotrophic chemical production in cyanobacteria.

  19. Bioconversion of glycerol for bioethanol production using isolated Escherichia coli ss1

    PubMed Central

    Suhaimi, Sheril Norliana; Phang, Lai-Yee; Maeda, Toshinari; Abd-Aziz, Suraini; Wakisaka, Minato; Shirai, Yoshihito; Hassan, Mohd Ali

    2012-01-01

    Bioconverting glycerol into various valuable products is one of glycerol's promising applications due to its high availability at low cost and the existence of many glycerol-utilizing microorganisms. Bioethanol and biohydrogen, which are types of renewable fuels, are two examples of bioconverted products. The objectives of this study were to evaluate ethanol production from different media by local microorganism isolates and compare the ethanol fermentation profile of the selected strains to use of glucose or glycerol as sole carbon sources. The ethanol fermentations by six isolates were evaluated after a preliminary screening process. Strain named SS1 produced the highest ethanol yield of 1.0 mol: 1.0 mol glycerol and was identified as Escherichia coli SS1 Also, this isolated strain showed a higher affinity to glycerol than glucose for bioethanol production. PMID:24031858

  20. [Construction and fermentation of a recombinant Candida glycerinogenes strain with high glycerol production].

    PubMed

    Liu, Ailing; Rao, Zhiming; Ma, Zheng; Zhuge, Bin; Fang, Huiying; Zhuge, Jian

    2009-06-01

    Candida glycerinogenes WL2002-5 (C.g) is an important industrial strain for glycerol production. To further improve glycerol production, we reconstructed a binary vector pCAM3300-zeocin-CgGPD1, introduced it to Agrobacterium tumefaciens LBA4404 by electroporation, and then transformed the T-DNA harboring the CgGPD1 to Candida glycerinogenes by Agrobacterium tumefaciens-mediated transformation (ATMT). After 96 h fermentation with glucose as the substrate, we screened a transformant named C.g-G8 with high glycerol production. Compared with the wild strain, the glucose consumption rate of C.g-G8 and the glycerol production were 12.97% and 18.06% higher, respectively. During the fermentation, the activity of glycerol-3-phosphate dehydrogenase of C.g-G8 was 27.55% higher than that of the wild strain. The recombinant Candida glycerinogenes with high glycerol production was successful constructed by ATMT method.

  1. Value-added processing of crude glycerol into chemicals and polymers.

    PubMed

    Luo, Xiaolan; Ge, Xumeng; Cui, Shaoqing; Li, Yebo

    2016-09-01

    Crude glycerol is a low-value byproduct which is primarily obtained from the biodiesel production process. Its composition is significantly different from that of pure glycerol. Crude glycerol usually contains various impurities, such as water, methanol, soap, fatty acids, and fatty acid methyl esters. Considerable efforts have been devoted to finding applications for converting crude glycerol into high-value products, such as biofuels, chemicals, polymers, and animal feed, to improve the economic viability of the biodiesel industry and overcome environmental challenges associated with crude glycerol disposal. This article reviews recent advances of biological and chemical technologies for value-added processing of crude glycerol into chemicals and polymers, and provides strategies for addressing production challenges.

  2. Natural nanocontainer for the controlled delivery of glycerol as a moisturizing agent.

    PubMed

    Suh, Y J; Kil, D S; Chung, K S; Abdullayev, E; Lvov, Y M; Mongayt, D

    2011-01-01

    Natural halloysite nanotubes with a 15-nm internal lumen and a 50 nm outer diameter were investigated as a nanocontainer for the loading and extended release of glycerol for cosmetic applications. Cytotoxicity testing of the halloysite was conducted on 3T3 and MCF-7 cells, and the tubules showed no toxic effect on the cells for over 48 h. The capability of halloysite for loading glycerol was higher with the USA halloysite than with the New Zealand's, being approximately 20% and 2.3% by weight, respectively. The total elapsed time for releasing glycerol from the nanotubes exceeded 20 h. To further retard the glycerol release rate, the halloysite samples filled with glycerol were coated with several alternate layers of polyethyleneimine and polyacrylic acid. The release rate remained at the same level, however, probably due to the low molecular weight of the polyelectrolytes and the high solubility of glycerol in water.

  3. Supercooling and vitrification of aqueous glycerol solutions at normal and high pressures.

    PubMed

    Miyata, K; Hayakawa, S; Kajiwara, K; Kanno, H

    2012-10-01

    The supercooling and vitrification of aqueous glycerol solutions was studied at high pressures. Homogeneous ice nucleation temperatures (T(H)) were obtained for aqueous glycerol solutions of R=50, 30, 20, 12, and 10 (R: moles of water/moles of glycerol) up to 300MPa. The R=20 glycerol solution formed a glass above 200MPa at a cooling rate of 200°C/min, indicating that pressure enhances glass-formation of aqueous glycerol solutions. The (dT(g)/dP) values were obtained for vitrified aqueous glycerol solutions of R=3, 5, 10, and 20. These data can be used for the development of cryo-preservation liquids for living cells at high pressures.

  4. Valorization of glycerol through the production of biopolymers: the PHB case using Bacillus megaterium.

    PubMed

    Naranjo, Javier M; Posada, John A; Higuita, Juan C; Cardona, Carlos A

    2013-04-01

    In this work technical and economic analyses were performed to evaluate the glycerol transformation into Polyhydroxybutyrate using Bacillus megaterium. The production of PHB was compared using glycerol or glucose as substrates and similar yields were obtained. The total production costs for PHB generation with both substrates were estimated at an industrial scale. Compared to glucose, glycerol showed a 10% and 20% decrease in the PHB production costs using two different separation schemes respectively. Moreover, a 20% profit margin in the PHB sales price using glycerol as substrate resulted in a 166% valorization of crude glycerol. In this work, the feasibility of glycerol as feedstock for the production of PHB at laboratory (up to 60% PHB accumulation) and industrial (2.6US$/kgPHB) scales is demonstrated.

  5. Electron beam irradiation of maltodextrin and cinnamyl alcohol mixtures: influence of glycerol on cross-linking.

    PubMed

    Khandal, Dhriti; Aggarwal, Manjeet; Suri, Gunjan; Coqueret, Xavier

    2015-03-06

    The influence of glycerol on the electron beam-induced changes in maltodextrins-cinnamyl alcohol (CA) blends is examined with respect to its influence on the degree of chain scission, grafting, and cross-linking. The study is relevant to radiation-induced polysaccharide modification, specifically in the perspective of using blended starch as a thermoplastic material, where glycerol is commonly used as a plasticizer. In the absence of CA, glycerol protects maltodextrin from chromophore formation onto the main chain, but also induces more chain scission. The presence of CA provides efficient radiation-protection against scission. Glycerol is shown to affect the interaction between maltodextrin and CA, most likely in the form of an inclusion complex when glycerol is absent. The global behavior under radiation is therefore governed by the physical interactions between the blend constituents rather than on the role of glycerol role as a plasticizer, or as an OH˙ radical scavenger.

  6. Anaerobic fermentation of glycerol in Paenibacillus macerans: metabolic pathways and environmental determinants.

    PubMed

    Gupta, Ashutosh; Murarka, Abhishek; Campbell, Paul; Gonzalez, Ramon

    2009-09-01

    Paenibacillus macerans is one of the species with the broadest metabolic capabilities in the genus Paenibacillus, able to ferment hexoses, deoxyhexoses, pentoses, cellulose, and hemicellulose. However, little is known about glycerol metabolism in this organism, and some studies have reported that glycerol is not fermented. Despite these reports, we found that several P. macerans strains are capable of anaerobic fermentation of glycerol. One of these strains, P. macerans N234A, grew fermentatively on glycerol at a maximum specific growth rate of 0.40 h(-1) and was chosen for further characterization. The use of [U-13C]glycerol and further analysis of extracellular metabolites and proteinogenic amino acids via nuclear magnetic resonance (NMR) spectroscopy allowed identification of ethanol, formate, acetate, succinate, and 1,2-propanediol (1,2-PDO) as fermentation products and demonstrated that glycerol is incorporated into cellular components. A medium formulation with low concentrations of potassium and phosphate, cultivation at acidic pH, and the use of a CO2-enriched atmosphere stimulated glycerol fermentation and are proposed to be environmental determinants of this process. The pathways involved in glycerol utilization and synthesis of fermentation products were identified using NMR spectroscopy in combination with enzyme assays. Based on these studies, the synthesis of ethanol and 1,2-PDO is proposed to be a metabolic determinant of glycerol fermentation in P. macerans N234A. Conversion of glycerol to ethanol fulfills energy requirements by generating one molecule of ATP per molecule of ethanol synthesized. Conversion of glycerol to 1,2-PDO results in the consumption of reducing equivalents, thus facilitating redox balance. Given the availability, low price, and high degree of reduction of glycerol, the high metabolic rates exhibited by P. macerans N234A are of paramount importance for the production of fuels and chemicals.

  7. Thermal Transitions and Extrusion of Glycerol-Plasticized Whey Protein Mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of glycerol and moisture contents on the thermal transitions of whey protein isolate (WPI) powder-glycerol-water mixtures were studied. Mixtures with ratios of 100:0, 70:30, 60:40 and 50:50 WPI:glycerol on a dry basis (db) were pre-conditioned to 0.34+/-0.01 (25.4±0.4ºC) and 0.48+/-0.02...

  8. Quantitative analysis of glycerol in dicarboxylic acid-rich cutins provides insights into Arabidopsis cutin structure.

    PubMed

    Yang, Weili; Pollard, Mike; Li-Beisson, Yonghua; Ohlrogge, John

    2016-10-01

    Cutin is an extracellular lipid polymer that contributes to protective cuticle barrier functions against biotic and abiotic stresses in land plants. Glycerol has been reported as a component of cutin, contributing up to 14% by weight of total released monomers. Previous studies using partial hydrolysis of cuticle-enriched preparations established the presence of oligomers with glycerol-aliphatic ester links. Furthermore, glycerol-3-phosphate 2-O-acyltransferases (sn-2-GPATs) are essential for cutin biosynthesis. However, precise roles of glycerol in cutin assembly and structure remain uncertain. Here, a stable isotope-dilution assay was developed for the quantitative analysis of glycerol by GC/MS of triacetin with simultaneous determination of aliphatic monomers. To provide clues about the role of glycerol in dicarboxylic acid (DCA)-rich cutins, this methodology was applied to compare wild-type (WT) Arabidopsis cutin with a series of mutants that are defective in cutin synthesis. The molar ratio of glycerol to total DCAs in WT cutins was 2:1. Even when allowing for a small additional contribution from hydroxy fatty acids, this is a substantially higher glycerol to aliphatic monomer ratio than previously reported for any cutin. Glycerol content was strongly reduced in both stem and leaf cutin from all Arabidopsis mutants analyzed (gpat4/gpat8, att1-2 and lacs2-3). In addition, the molar reduction of glycerol was proportional to the molar reduction of total DCAs. These results suggest "glycerol-DCA-glycerol" may be the dominant motif in DCA-rich cutins. The ramifications and caveats for this hypothesis are presented.

  9. Exploring the thermoelectric and magnetic properties of uranium selenides: Tl2Ag2USe4 and Tl3Cu4USe6

    NASA Astrophysics Data System (ADS)

    Azam, Sikander; Khan, Saleem Ayaz; Din, Haleem Ud; Khenata, Rabah; Goumri-Said, Souraya

    2016-09-01

    The electronic, magnetic and thermoelectric properties of Tl2Ag2USe4 and Tl3Cu4USe6 compounds were investigated using the full potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The exchange correlation was treated with the generalized gradient approximation plus optimized effective Hubbard parameter and spin-orbit coupling (GGA+U+SOC). The present uranium selenides show narrow direct energy band gap values of 0.7 and 0.875 eV for Tl2Ag2USe4 and Tl3Cu4USe6 respectively. For both selenides U-d/f states are responsible for electrical transport properties. Uranium atoms were the most contributors in the magnetic moment compared to other atoms and show ferromagnetic nature. The spin density isosurfaces show the polarization of neighboring atoms of Uranium, such as silver/copper and selenium. Thermoelectric calculations reveal that Tl3Cu4USe6 is more suitable for thermoelectric device applications than Tl2Ag2USe4.

  10. A self-cleaning coating based on commercial grade polyacrylic latex modified by TiO2/Ag-exchanged-zeolite-A nanocomposite

    NASA Astrophysics Data System (ADS)

    Nosrati, Rahimeh; Olad, Ali; Nofouzi, Katayoon

    2015-08-01

    The commercial grade polyacrylic latex was modified in order to prepare a self-cleaning coating. TiO2/Ag-exchanged-zeolite-A nanocomposite was prepared and used as additive in the matrix of polyacrylic latex to achieve a hydrophilic and photocatalytic coating. FTIR and UV-visible spectroscopy, X-ray diffraction patterns and FESEM were used to characterize the composition and structure of the nanocomposites and coatings. The acrylic coatings, were prepared by using of TiO2/Ag-exchanged-zeolite-A additive, had better UV and visible light absorption, hydrophilic, degradation of organic pollutants, stability in water and antimicrobial properties than pristine commercial grade polyacrylic latex coating. According to the results, the modified polyacrylic based coating containing 0.5 wt% of TiO2/Ag-exchanged-zeolite-A nanocomposite additive with TiO2 to Ag-exchanged-zeolite-A ratio of 1:2 was the best coating considering most of useful properties such as small band gap and low water contact angle. The water contact angle for unmodified polyacrylic latex coating was 68° which was decreased to less than 10° in modified coating after 24 h LED lamp illumination.

  11. A novel ethanol gas sensor based on TiO2/Ag0.35V2O5 branched nanoheterostructures

    PubMed Central

    Wang, Yuan; Liu, Lixin; Meng, Chuanmin; Zhou, Yun; Gao, Zhao; Li, Xuhai; Cao, Xiuxia; Xu, Liang; Zhu, Wenjun

    2016-01-01

    Much greater surface-to-volume ratio of hierarchical nanostructures renders them attract considerable interest as prototypical gas sensors. In this work, a novel resistive gas sensor based on TiO2/Ag0.35V2O5 branched nanoheterostructures is fabricated by a facile one-step synthetic process and the ethanol sensing performance of this device is characterized systematically, which shows faster response/recovery behavior, better selectivity, and higher sensitivity of about 9 times as compared to the pure TiO2 nanofibers. The enhanced sensitivity of the TiO2/Ag0.35V2O5 branched nanoheterostructures should be attributed to the extraordinary branched hierarchical structures and TiO2/Ag0.35V2O5 heterojunctions, which can eventually result in an obvious change of resistance upon ethanol exposure. This study not only indicates the gas sensing mechanism for performance enhancement of branched nanoheterostructures, but also proposes a rational approach to design nanostructure based chemical sensors with desirable performance. PMID:27615429

  12. Sequential laser and ultrasonic wave generation of TiO2@Ag core-shell nanoparticles and their anti-bacterial properties.

    PubMed

    Hamad, Abubaker Hassan; Li, Lin; Liu, Zhu; Zhong, Xiang Li; Wang, Tao

    2016-02-01

    Core-shell nanoparticles have unusual physical, chemical and biological properties. Until now, for the Ag and TiO2 combination, only Ag core and TiO2 shell nanoparticles have been practically demonstrated. In this investigation, novel TiO2@Ag core-shell (TiO2 core and Ag shell) nanoparticles were produced via ultrasonic vibration of Ag-TiO2 compound nanoparticles. A bulk Ti/Ag alloy plate was used to generate colloidal Ag-TiO2 compound nanoparticles via picosecond laser ablation in deionised water. The colloidal nanoparticles were then sonicated in an ultrasonic bath to generate TiO2@Ag core-shell nanoparticles. They were characterised using a UV-VIS spectrometer, transmission electron microscopy (TEM), high-angle annular dark-field-Scanning transmission electron microscopy (HAADF-STEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The Ag-TiO2 compound and the TiO2@Ag core-shell nanoparticles were examined for their antibacterial activity against Escherichia coli (E. coli) JM109 strain bacteria and compared with those of Ag and TiO2 nanoparticles. The antibacterial activity of the core-shell nanoparticles was slightly better than that of the compound nanoparticles at the same concentration under standard laboratory light conditions and both were better than the TiO2 nanoparticles but not as good as the Ag nanoparticles.

  13. A Simple Method for the Preparation of TiO2 /Ag-AgCl@Polypyrrole Composite and Its Enhanced Visible-Light Photocatalytic Activity.

    PubMed

    Yao, Tongjie; Shi, Lei; Wang, Hao; Wang, Fangxiao; Wu, Jie; Zhang, Xiao; Sun, Jianmin; Cui, Tieyu

    2016-01-01

    A novel and facile method was developed to prepare a visible-light driven TiO2 /Ag-AgCl@polypyrrole (PPy) photocatalyst with Ag-AgCl nanoparticles supported on TiO2 nanofibers and covered by a thin PPy shell. During the synthesis, the PPy shell and Ag-AgCl nanoparticles were prepared simultaneously onto TiO2 nanofibers, which simplified the preparation procedure. In addition, because Ag-AgCl aggregates were fabricated via partly etching the Ag nanoparticles, their size was well controlled at the nanoscale, which was beneficial for improvement of the contact surface area. Compared with reference photocatalysts, the TiO2 /Ag-AgCl@PPy composite exhibited an enhanced photodegradation activity towards rhodamine B under visible-light irradiation. The superior photocatalytic property originated from synergistic effects between TiO2 nanofibers, Ag-AgCl nanoparticles and the PPy shell. Furthermore, the TiO2 /Ag-AgCl@PPy composite could be easily separated and recycled without obvious reduction in activity.

  14. Highly sensitive surface-enhanced Raman scattering detection of hexavalent chromium based on hollow sea urchin-like TiO2@Ag nanoparticle substrate.

    PubMed

    Zhou, Wen; Yin, Bin-Cheng; Ye, Bang-Ce

    2017-01-15

    As one of the most toxic heavy metals, hexavalent chromium (Cr(VI)) has long been a concern due to its threats to human health and the environment. In this work, we develop a sensitive surface-enhanced Raman scattering (SERS) sensor for highly specific detection of Cr(VI) using hollow sea urchin-like TiO2@Ag nanoparticles (NPs). The TiO2@Ag NPs are functionalized with glutathione (GSH) and used as substrates with 2-mercaptopyridine (2-MPy) as a Raman reporter for a recyclable SERS-active sensor, enabling ultrasensitive detection of Cr(VI). Excellent SERS signals of 2-MPy reporters are detected when GSH complexation with Cr(VI) causes aggregation of the TiO2@Ag NPs. The developed sensor exhibits good linearity in the range from 10nM to 2μM for Cr(VI) with a detection limit of ca. 1.45nM. It features excellent selectivity to Cr(VI) over other interfering metal ions, and good application for quantitative analysis of Cr(VI) in water samples. Moreover, the proposed SERS sensor can be fully regenerated when exposed to UV light as a result of the self-cleaning ability of the substrates. In contrast to the traditional SERS detection, the present work shed new light on the design and synthesis of hierarchically self-assembled 3D substrate for SERS, catalysis and biosensor development.

  15. Novel Fe3O4@SiO2@Ag@Ni trepang-like nanocomposites: High-efficiency and magnetic recyclable catalysts for organic dye degradation

    NASA Astrophysics Data System (ADS)

    Li, Chao; Sun, Jun-Jie; Chen, Duo; Han, Guang-Bing; Yu, Shu-Yun; Kang, Shi-Shou; Mei, Liang-Mo

    2016-08-01

    A facile step-by-step approach is developed for synthesizing the high-efficiency and magnetic recyclable Fe3O4@SiO2@Ag@Ni trepang-like nanocomposites. This method involves coating Fe2O3 nanorods with a uniform silica layer, reduction in 10% H2/Ar atmosphere to transform the Fe2O3 into magnetic Fe3O4, and finally depositing Ag@Ni core-shell nanoparticles on the L-lysine modified surface of Fe3O4@SiO2 nanorods. The fabricated nanocomposites are further characterized by x-ray diffraction, transmission electron microscopy, scanning electron microscope, Fourier transform infrared spectroscopy, and inductively coupled plasma mass spectroscopy. The Fe3O4@SiO2@Ag@Ni trepang-like nanocomposites exhibit remarkably higher catalytic efficiency than monometallic Fe3O4@SiO2@Ag nanocomposites toward the degradation of Rhodamine B (RhB) at room temperature, and maintain superior catalytic activity even after six cycles. In addition, these samples could be easily separated from the catalytic system by an external magnet and reused, which shows great potential applications in treating waste water. Project supported by the National Basic Research Program of China (Grant No. 2015CB921502), the National Natural Science Foundation of China (Grant Nos. 11474184 and 11174183), the 111 Project (Grant No. B13029), and the Fundamental Research Funds of Shandong University, China.

  16. A novel ethanol gas sensor based on TiO2/Ag0.35V2O5 branched nanoheterostructures

    NASA Astrophysics Data System (ADS)

    Wang, Yuan; Liu, Lixin; Meng, Chuanmin; Zhou, Yun; Gao, Zhao; Li, Xuhai; Cao, Xiuxia; Xu, Liang; Zhu, Wenjun

    2016-09-01

    Much greater surface-to-volume ratio of hierarchical nanostructures renders them attract considerable interest as prototypical gas sensors. In this work, a novel resistive gas sensor based on TiO2/Ag0.35V2O5 branched nanoheterostructures is fabricated by a facile one-step synthetic process and the ethanol sensing performance of this device is characterized systematically, which shows faster response/recovery behavior, better selectivity, and higher sensitivity of about 9 times as compared to the pure TiO2 nanofibers. The enhanced sensitivity of the TiO2/Ag0.35V2O5 branched nanoheterostructures should be attributed to the extraordinary branched hierarchical structures and TiO2/Ag0.35V2O5 heterojunctions, which can eventually result in an obvious change of resistance upon ethanol exposure. This study not only indicates the gas sensing mechanism for performance enhancement of branched nanoheterostructures, but also proposes a rational approach to design nanostructure based chemical sensors with desirable performance.

  17. Effect of crude glycerol-derived inhibitors on ethanol production by Enterobacter aerogenes.

    PubMed

    Lee, Sang Jun; Kim, Sung Bong; Kang, Seong Woo; Han, Sung Ok; Park, Chulhwan; Kim, Seung Wook

    2012-01-01

    In this study, ethanol production from pure and crude glycerol using Enterobacter aerogenes ATCC 29007 was evaluated under anaerobic culture conditions. Inhibitory effects of substrate concentrations, pH, and salt concentrations were investigated based on crude glycerol components. Ethanol production was performed with pure glycerol concentrations ranging from 5 to 30 g/L to evaluate the effects of substrate concentration and osmotic pressure. The consumed glycerol was 5-14.33 g/L, and the yield of ethanol was higher than 0.75 mol ethanol/mol glycerol after 24 h of cultivation. To evaluate the inhibitory effects of salts (NaCl and KCl), experiments were performed with 0-20 g/L of each salt. Inhibitory effects of salts were strongest at high salt concentrations. The inhibitory effect of pH was performed in the pH range 4-10, and cell growth and ethanol production were highest at pH 5-6. Also, ethanol production was slightly inhibited at low concentration of crude glycerol comparison with pure glycerol. However, significant inhibitory effects were not observed at 1.5 and 2% crude glycerol which showed higher ethanol production compared to pure glycerol.

  18. Engineering of the glycerol decomposition pathway and cofactor regulation in an industrial yeast improves ethanol production.

    PubMed

    Zhang, Liang; Tang, Yan; Guo, Zhongpeng; Shi, Guiyang

    2013-10-01

    Glycerol is a major by-product of industrial ethanol production and its formation consumes up to 4 % of the sugar substrate. This study modified the glycerol decomposition pathway of an industrial strain of Saccharomyces cerevisiae to optimize the consumption of substrate and yield of ethanol. This study is the first to couple glycerol degradation with ethanol formation, to the best of our knowledge. The recombinant strain overexpressing GCY1 and DAK1, encoding glycerol dehydrogenase and dihydroxyacetone kinase, respectively, in glycerol degradation pathway, exhibited a moderate increase in ethanol yield (2.9 %) and decrease in glycerol yield (24.9 %) compared to the wild type with the initial glucose concentration of 15 % under anaerobic conditions. However, when the mhpF gene, encoding acetylating NAD⁺-dependent acetaldehyde dehydrogenase from Escherichia coli, was co-expressed in the aforementioned recombinant strain, a further increase in ethanol yield by 5.5 % and decrease in glycerol yield by 48 % were observed for the resultant recombinant strain GDMS1 when acetic acid was added into the medium prior to inoculation compared to the wild type. The process outlined in this study which enhances glycerol consumption and cofactor regulation in an industrial yeast is a promising metabolic engineering strategy to increase ethanol production by reducing the formation of glycerol.

  19. Determination of glycerol in oils and fats using liquid chromatography chloride attachment electrospray ionization mass spectrometry.

    PubMed

    Jin, Chunfen; Viidanoja, Jyrki

    2017-01-15

    Existing liquid chromatography - mass spectrometry method for the analysis of short chain carboxylic acids was expanded and validated to cover also the measurement of glycerol from oils and fats. The method employs chloride anion attachment and two ions, [glycerol+(35)Cl](-) and [glycerol+(37)Cl](-), as alternative quantifiers for improved selectivity of glycerol measurement. The averaged within run precision, between run precision and accuracy ranged between 0.3-7%, 0.4-6% and 94-99%, respectively, depending on the analyte ion and sample matrix. Selected renewable diesel feedstocks were analyzed with the method.

  20. Enzymatic coproduction of biodiesel and glycerol carbonate from soybean oil in solvent-free system.

    PubMed

    Go, A-Ra; Lee, Youngrak; Kim, Young Hwan; Park, Sehkyu; Choi, Joongso; Lee, Jinwon; Han, Sung Ok; Kim, Seung Wook; Park, Chulhwan

    2013-08-15

    The enzymatic coproduction of biodiesel and glycerol carbonate by transesterification of soybean oil and dimethyl carbonate (DMC) has been studied in a solvent-free system. The effects on biodiesel and glycerol carbonate conversion of reaction conditions including the kind of enzyme, the amount of enzyme, the molar ratio of DMC to soybean oil, the reaction temperature, and water addition were investigated. The optimal conditions for biodiesel and glycerol carbonate were 20% Novozym 435, 10:1 molar ratio of DMC to soybean oil, and 0.7% water addition. Under these conditions, the conversions of 96.4% biodiesel and 92.1% glycerol carbonate have been achieved after 48h.

  1. Microbial synthesis of polyhydroxybutyrate from glycerol: gluconeogenesis, molecular weight and material properties of biopolyester.

    PubMed

    Tanadchangsaeng, Nuttapol; Yu, Jian

    2012-11-01

    Glycerol is considered as an ideal feedstock for producing bioplastics via bacterial fermentation due to its ubiquity, low price, and high degree of reduction substrate. In this work, we study the yield and cause of limitation in poly(3-hydroxybutyrate) (PHB) production from glycerol. Compared to glucose-based PHB production, PHB produced by Cupriavidus necator grown on glycerol has a low productivity (0.92 g PHB/L/h) with a comparably low maximum specific growth rate of 0.11 h(-1) . We found that C. necator can synthesize glucose from glycerol and that the lithotrophical utilization of glycerol (non-fermentative substrate) or gluconeogenesis is an essential metabolic pathway for biosynthesis of cellular components. Here, we show that gluconeogenesis affects the reduction of cell mass, the productivity of biopolymer product, and the molecular chain size of intracellular PHB synthesized from glycerol by C. necator. We use NMR spectroscopy to show that the isolated PHB is capped by glycerol. We then characterized the physical properties of the isolated glycerol-based PHB with differential scanning calorimetry and tensile tests. We found that although the final molecular weight of the glycerol-based PHB is lower than those of glucose-based and commercial PHB, the thermal and mechanical properties of the biopolymers are similar.

  2. Effects of deletion of glycerol-3-phosphate dehydrogenase and glutamate dehydrogenase genes on glycerol and ethanol metabolism in recombinant Saccharomyces cerevisiae.

    PubMed

    Kim, Jin-Woo; Chin, Young-Wook; Park, Yong-Cheol; Seo, Jin-Ho

    2012-01-01

    Bioethanol is currently used as an alternative fuel for gasoline worldwide. For economic production of bioethanol by Saccharomyces cerevisiae, formation of a main by-product, glycerol, should be prevented or minimized in order to reduce a separation cost of ethanol from fermentation broth. In this study, S. cerevisiae was engineered to investigate the effects of the sole and double disruption of NADH-dependent glycerol-3-phosphate dehydrogenase 1 (GPD1) and NADPH-requiring glutamate dehydrogenase 1 (GDH1) on the production of glycerol and ethanol from glucose. Even though sole deletion of GPD1 or GDH1 reduced glycerol production, double deletion of GPD1 and GDH1 resulted in the lowest glycerol concentration of 2.31 g/L, which was 46.4% lower than the wild-type strain. Interestingly, the recombinant S. cerevisiae ∆GPD1∆GDH1 strain showed a slight improvement in ethanol yield (0.414 g/g) compared with the wild-type strain (0.406 g/g). Genetic engineering of the glycerol and glutamate metabolic pathways modified NAD(P)H-requiring metabolic pathways and exerted a positive effect on glycerol reduction without affecting ethanol production.

  3. Pre-exercise glycerol hydration improves cycling endurance time

    NASA Technical Reports Server (NTRS)

    Montner, P.; Stark, D. M.; Riedesel, M. L.; Murata, G.; Robergs, R.; Timms, M.; Chick, T. W.

    1996-01-01

    The effects of glycerol ingestion (GEH) on hydration and subsequent cycle ergometer submaximal load exercise were examined in well conditioned subjects. We hypothesized that GEH would reduce physiologic strain and increase endurance. The purpose of Study I (n = 11) was to determine if pre-exercise GEH (1.2 gm/kg glycerol in 26 ml/kg solution) compared to pre-exercise placebo hydration (PH) (26 ml/kg of aspartame flavored water) lowered heart rate (HR), lowered rectal temperature (Tc), and prolonged endurance time (ET) during submaximal load cycle ergometry. The purpose of Study II (n = 7) was to determine if the same pre-exercise regimen followed by carbohydrate oral replacement solution (ORS) during exercise also lowered HR, Tc, and prolonged ET. Both studies were double-blind, randomized, crossover trials, performed at an ambient temperature of 23.5-24.5 degrees C, and humidity of 25-27%. Mean HR was lower by 2.8 +/- 0.4 beats/min (p = 0.05) after GEH in Study I and by 4.4 +/- 1.1 beats/min (p = 0.01) in Study II. Endurance time was prolonged after GEH in Study I (93.8 +/- 14 min vs. 77.4 +/- 9 min, p = 0.049) and in Study II (123.4 +/- 17 min vs. 99.0 +/- 11 min, p = 0.03). Rectal temperature did not differ between hydration regimens in both Study I and Study II. Thus, pre-exercise glycerol-enhanced hyperhydration lowers HR and prolongs ET even when combined with ORS during exercise. The regimens tested in this study could potentially be adapted for endurance activities.

  4. Self-assembling behavior of glycerol monoundecenoate in water.

    PubMed

    Nyame Mendendy Boussambe, Gildas; Valentin, Romain; Fabre, Jean-François; Navailles, Laurence; Nallet, Frédéric; Gaillard, Cedric; Mouloungui, Zephirin

    2017-03-14

    Self-assembling properties of glycerol esters in water are well known. Still, few data on glyc-erol monoesters of undecylenic acid are available. The aim of this study was to highlight the behavior of the glycerol monoundecenoate (GM-C11:1) in different, diluted and concentrated states. Self-assembling properties in water and upon solid inorganic surfaces were investigated in diluted state with surface tension experiments, AFM and Cryo-TEM studies. In concen-trated state, the gelling properties in presence of water were investigated by polarized light microscopy, DSC and SAXS experiments. GM-C11:1 at 100 mg/L self-assembles at the liq-uid/air interfaces as aggregates of about 20 nm in diameter, organized into concentric forms. These aggregates were spherical globules composed of several molecules of GM-C11:1. At higher concentrations (1000 mg/L and 104 mg/L), GM-C11:1 was able to coat uniformly liq-uid/air and liquid/solid interfaces. In bulk GM-C11:1 form spontaneously aggregates and ves-icles. In more concentrated state, GM-C11:1 assembles into lamellar Lβ and Lα form in water. By cross-referencing SAXS and DSC findings, we were able to distinguish between interla-mellar water molecules strongly bound to GM-C11:1 and other molecules remaining unbound and considered as "mobile" water. The percentage of water strongly bound was proportional to the percentage of GM-C11:1 in the system. In this case, GM-C11:1 appears to be an effec-tive molecule for surface treatments for which water retention is important.

  5. Glycerol effects on protein flexibility: a tryptophan phosphorescence study.

    PubMed Central

    Gonnelli, M.; Strambini, G. B.

    1993-01-01

    In exploring the dynamic properties of protein structure, numerous studies have focussed on the dependence of structural fluctuations on solvent viscosity, but the emerging picture is still not well defined. Exploiting the sensitivity of the phosphorescence lifetime of tryptophan to the viscosity of its environment we have used the delayed emission as an intrinsic probe of protein flexibility and investigated the effects of glycerol as a viscogenic cosolvent. The phosphorescence lifetime of alcohol dehydrogenase, alkaline phosphatase, apoazurin and RNase T1, as a function of glycerol concentration was studied at various temperatures. Flexibility data, which refer to rather rigid sites of the globular structures, point out that, for some concentration ranges glycerol, effects on the rate of structural fluctuations of alcohol dehydrogenase and RNase T1 do not obey Kramers' a power law on solvent viscosity and emphasize that cosolvent-induced structural changes can be important, even for inner cores of the macromolecule. When the data is analyzed in terms of Kramers' model, for the temperature range 0-30 degrees C one derives frictional coefficients that are relatively large (0.6-0.7) for RNase T1, where the probe is in a flexible region near the surface of the macromolecule and much smaller, less than 0.2, for the rigid sites of the other proteins. For the latter sites the frictional coefficient rises sharply between 40 and 60 degrees C, and its value correlates weakly with molecular parameters such as the depth of burial or the rigidity of a particular site. For RNase T1, coupling to solvent viscosity increases at subzero temperatures, with the coefficient becoming as large as 1 at -20 degrees C. Temperature effects were interpreted by proposing that solvent damping of internal protein motions is particularly effective for low frequency, large amplitude, structural fluctuations yielding highly flexible conformers of the macromolecule. PMID:8369422

  6. Scattering of water from the glycerol liquid-vacuum interface

    NASA Technical Reports Server (NTRS)

    Benjamin, I.; Wilson, M. A.; Pohorille, A.; Nathanson, G. M.

    1995-01-01

    Molecular dynamics calculations of the scattering of D2O from the glycerol surface at different collision energies are reported. The results for the trapping probabilities and energy transfer are in good agreement with experiments. The calculations demonstrate that the strong attractive forces between these two strongly hydrogen bonding molecules have only a minor effect on the initial collision dynamics. The trapping probability is influenced to a significant extent by the repulsive hard sphere-like initial encounter with the corrugated surface and, only at a later stage, by the efficiency of energy flow in the multiple interactions between the water and the surface molecules.

  7. L (+)-lactic acid production by pellet-form Rhizopus oryzae NRRL 395 on biodiesel crude glycerol

    PubMed Central

    2013-01-01

    Background Given its availability and low price, glycerol derived from biodiesel industry has become an ideal feedstock for the production of fuels and chemicals. A solution to reduce the negative environmental problems and the cost of biodiesel is to use crude glycerol as carbon source for microbial growth media in order to produce valuable organic chemicals. In the present paper, crude glycerol was used as carbon substrate for production of L (+)-lactic acid using pelletized fungus R. oryzae NRRL 395 on batch fermentation. More, the experiments were conducted on media supplemented with inorganic nutrients and lucerne green juice. Results Crude and pure glycerols were first used to produce the highest biomass yield of R. oryzae NRRL 395. An enhanced lactic acid production then followed up using fed-batch fermentation with crude glycerol, inorganic nutrients and lucerne green juice. The optimal crude glycerol concentration for cultivating R. oryzae NRRL 395 was 75 g l-1, which resulted in a fungal biomass yield of 0.72 g g-1 in trial without lucerne green juice addition and 0.83 g g-1 in trial with lucerne green juice. The glycerol consumption rate was 1.04 g l-1 h-1 after 48 h in trial with crude glycerol 75 g l-1 while in trial with crude glycerol 10 g l-1 the lowest rate of 0.12 g l-1 h-1 was registered. The highest L (+)-lactic acid yield (3.72 g g-1) was obtained at the crude glycerol concentration of 75 g l-1 and LGJ 25 g l-1, and the concentration of lactic acid was approximately 48 g l-1. Conclusions This work introduced sustainable opportunities for L (+)-lactic acid production via R. oryzae NRRL 395 fermentation on biodiesel crude glycerol media. The results showed good fungal growth on crude glycerol at 75 g l-1 concentration with lucerne green juice supplementation of 25 g l-1. Lucerne green juice provided a good source of nutrients for crude glycerol fermentation, without needs for supplementation with inorganic nutrients

  8. Use of molecular dynamics to assess the biophysiological role of hydroxyl groups in glycerol dyalkyl glycerol teraethers

    NASA Astrophysics Data System (ADS)

    Huguet, Carme; Costenaro, Lionel; Fietz, Susanne; Daura, Xavier

    2015-04-01

    The cell membrane of some Archaea is constituted by lipids that span the whole membrane width and contain two alkyl chains bound by two glycerol groups (glycerol dyalkyl glycerol teraethers or GDGTs). These lipids confer stability to the membrane in mesophile to extremophile environments. Besides the more frequently studied isoprenoid archaeal lipids, both mono- and dihydroxy-GDGTs (OH-GDGT) have been recently reported to occur in marine sediments (1). OH-GDGTs contain up to two cyclopentane moieties and have been identified in both core and intact forms. In 2013, a correlation between OH-GDGTs and temperature was reported, with higher relative OH-GDGT abundances at high latitudes (2,3). The physiological function of the hydroxyl group in a GDGT is not yet known, but given the field results, it could be linked to an adaptation of the membrane to changes in temperature. For hydroxydiether lipid cores in methanogenic bacteria, it has been postulated that the hydroxyl group may alter the cell membrane properties: either extending the polar head group region or creating a hydrophilic pocket (4). It has also been suggested that the hydroxylation of the biphytany (l) moiety may result in enhanced membrane rigidity (1). To improve our understanding of the effect of the hydroxylation on physical properties of membranes, we performed molecular-dynamics simulations of GDGT membranes presenting and lacking these additional OH groups. This is an approach with a great development potential in the archaea lipid field, especially in relation to proxy validation. Our results indicate that the addition of an OH increases the membrane fluidity, thus providing an advantage in cold environments. We also observe a widening of the polar head group area, which could enhance transport. 1. Liu et al. 2012, GCA 2. Huguet et al. 2013, Org. Geochem 3. Fietz et al. 2013 4. Sprott et al. 1990. J. Biol. Chem. 265, 13735-13740.

  9. Anticipatory and consummatory effects of (hedonic) chocolate intake are associated with increased circulating levels of the orexigenic peptide ghrelin and endocannabinoids in obese adults

    PubMed Central

    Rigamonti, Antonello E.; Piscitelli, Fabiana; Aveta, Teresa; Agosti, Fiorenza; De Col, Alessandra; Bini, Silvia; Cella, Silvano G.; Di Marzo, Vincenzo; Sartorio, Alessandro

    2015-01-01

    Background Hedonic hunger refers to consumption of food just for pleasure and not to maintain energy homeostasis. Recently, consumption of food for pleasure was reported to be associated with increased circulating levels of both the orexigenic peptide ghrelin and the endocannabinoid 2-arachidonoyl-glycerol (2-AG) in normal-weight subjects. To date, the effects of hedonic hunger, and in particular of chocolate craving, on these mediators in obese subjects are still unknown. Methods To explore the role of some gastrointestinal orexigenic and anorexigenic peptides and endocannabinoids (and some related congeners) in chocolate consumption, we measured changes in circulating levels of ghrelin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY), anandamide (AEA), 2-AG, palmitoylethanolamide (PEA), and oleoylethanolamide (OEA) in 10 satiated severely obese subjects after consumption of chocolate and, on a separate day, of a non-palatable isocaloric food with the same bromatologic composition. Evaluation of hunger and satiety was also performed by visual analogic scale. Results The anticipatory phase and the consumption of food for pleasure were associated with increased circulating levels of ghrelin, AEA, 2-AG, and OEA. In contrast, the levels of GLP-1, PYY, and PEA did not differ before and after the exposure/ingestion of either chocolate or non-palatable foods. Hunger and satiety were higher and lower, respectively, in the hedonic session than in the non-palatable one. Conclusions When motivation to eat is generated by exposure to, and consumption of, chocolate a peripheral activation of specific endogenous rewarding chemical signals, including ghrelin, AEA, and 2-AG, is observed in obese subjects. Although preliminary, these findings predict the effectiveness of ghrelin and endocannabinoid antagonists in the treatment of obesity. PMID:26546790

  10. Monoglyceride lipase deficiency causes desensitization of intestinal cannabinoid receptor type 1 and increased colonic μ-opioid receptor sensitivity

    PubMed Central

    Taschler, U; Eichmann, T O; Radner, F P W; Grabner, G F; Wolinski, H; Storr, M; Lass, A; Schicho, R; Zimmermann, R

    2015-01-01

    Background and Purpose Monoglyceride lipase (MGL) degrades 2-arachidonoyl glycerol (2-AG), an endogenous agonist of cannabinoid receptors (CB1/2). Because the CB1 receptor is involved in the control of gut function, we investigated the effects of pharmacological inhibition and genetic deletion of MGL on intestinal motility. Furthermore, we determined whether defective 2-AG degradation affects μ-opioid receptor (μ receptor) signalling, a parallel pathway regulating gut motility. Experimental Approach Gut motility was investigated by monitoring Evans Blue transit and colonic bead propulsion in response to MGL inhibition and CB1 receptor or μ receptor stimulation. Ileal contractility was investigated by electrical field stimulation. CB1 receptor expression in ileum and colon was assessed by immunohistochemical analyses. Key Results Pharmacological inhibition of MGL slowed down whole gut transit in a CB1 receptor-dependent manner. Conversely, genetic deletion of MGL did not affect gut transit despite increased 2-AG levels. Notably, MGL deficiency caused complete insensitivity to CB1 receptor agonist-mediated inhibition of whole gut transit and ileal contractility suggesting local desensitization of CB1 receptors. Accordingly, immunohistochemical analyses of myenteric ganglia of MGL-deficient mice revealed that CB1 receptors were trapped in endocytic vesicles. Finally, MGL-deficient mice displayed accelerated colonic propulsion and were hypersensitive to μ receptor agonist-mediated inhibition of colonic motility. This phenotype was reproduced by chronic pharmacological inhibition of MGL. Conclusion and Implications Constantly elevated 2-AG levels induce severe desensitization of intestinal CB1 receptors and increased sensitivity to μ receptor-mediated inhibition of colonic motility. These changes should be considered when cannabinoid-based drugs are used in the therapy of gastrointestinal diseases. PMID:26075589

  11. Requirement of cannabinoid CB(1) receptors in cortical pyramidal neurons for appropriate development of corticothalamic and thalamocortical projections.

    PubMed

    Wu, Chia-Shan; Zhu, Jie; Wager-Miller, Jim; Wang, Shan; O'Leary, Dennis; Monory, Krisztina; Lutz, Beat; Mackie, Ken; Lu, Hui-Chen

    2010-09-01

    A role for endocannabinoid signaling in neuronal morphogenesis as the brain develops has recently been suggested. Here we used the developing somatosensory circuit as a model system to examine the role of endocannabinoid signaling in neural circuit formation. We first show that a deficiency in cannabinoid receptor type 1 (CB(1)R), but not G-protein-coupled receptor 55 (GPR55), leads to aberrant fasciculation and pathfinding in both corticothalamic and thalamocortical axons despite normal target recognition. Next, we localized CB(1)R expression to developing corticothalamic projections and found little if any expression in thalamocortical axons, using a newly established reporter mouse expressing GFP in thalamocortical projections. A similar thalamocortical projection phenotype was observed following removal of CB(1)R from cortical principal neurons, clearly demonstrating that CB(1)R in corticothalamic axons was required to instruct their complimentary connections, thalamocortical axons. When reciprocal thalamic and cortical connections meet, CB(1)R-containing corticothalamic axons are intimately associated with elongating thalamocortical projections containing DGLβ, a 2-arachidonoyl glycerol (2-AG) synthesizing enzyme. Thus, 2-AG produced in thalamocortical axons and acting at CB(1)Rs on corticothalamic axons is likely to modulate axonal patterning. The presence of monoglyceride lipase, a 2-AG degrading enzyme, in both thalamocortical and corticothalamic tracts probably serves to restrict 2-AG availability. In summary, our study provides strong evidence that endocannabinoids are a modulator for the proposed 'handshake' interactions between corticothalamic and thalamocortical axons, especially for fasciculation. These findings are important in understanding the long-term consequences of alterations in CB(1)R activity during development, a potential etiology for the mental health disorders linked to prenatal cannabis use.

  12. A Primary Cortical Input to Hippocampus Expresses a Pathway-Specific and Endocannabinoid-Dependent Form of Long-Term Potentiation

    PubMed Central

    Wang, Weisheng; Jia, Yousheng; Pham, Danielle T.; Karsten, Carley A.; Merrill, Collin B.; Gall, Christine M.; Piomelli, Daniele

    2016-01-01

    Abstract The endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG), a key modulator of synaptic transmission in mammalian brain, is produced in dendritic spines and then crosses the synaptic junction to depress neurotransmitter release. Here we report that 2-AG-dependent retrograde signaling also mediates an enduring enhancement of glutamate release, as assessed with independent tests, in the lateral perforant path (LPP), one of two cortical inputs to the granule cells of the dentate gyrus. Induction of this form of long-term potentiation (LTP) involved two types of glutamate receptors, changes in postsynaptic calcium, and the postsynaptic enzyme that synthesizes 2-AG. Stochastic optical reconstruction microscopy confirmed that CB1 cannabinoid receptors are localized presynaptically to LPP terminals, while the inhibition or knockout of the receptors eliminated LPP-LTP. Suppressing the enzyme that degrades 2-AG dramatically enhanced LPP potentiation, while overexpressing it produced the opposite effect. Priming with a CB1 agonist markedly reduced the threshold for LTP. Latrunculin A, which prevents actin polymerization, blocked LPP-LTP when applied extracellularly but had no effect when infused postsynaptically into granule cells, indicating that critical actin remodeling resides in the presynaptic compartment. Importantly, there was no evidence for the LPP form of potentiation in the Schaffer-commissural innervation of field CA1 or in the medial perforant path. Peripheral injections of compounds that block or enhance LPP-LTP had corresponding effects on the formation of long-term memory for cues conveyed to the dentate gyrus by the LPP. Together, these results indicate that the encoding of information carried by a principal hippocampal afferent involves an unusual, regionally differentiated form of plasticity. PMID:27517090

  13. Crystal structure of substrate free form of glycerol dehydratase

    SciTech Connect

    Liao, Der-Ing; Dotson, Garry; Turner, Jr., Ivan; Reiss, Lisa; Emptage, Mark

    2010-03-08

    Glycerol dehydratase (GDH) and diol dehydratase (DDH) are highly homologous isofunctional enzymes that catalyze the elimination of water from glycerol and 1,2-propanediol (1,2-PD) to the corresponding aldehyde via a coenzyme B{sub 12}-dependent radical mechanism. The crystal structure of substrate free form of GDH in complex with cobalamin and K{sup +} has been determined at 2.5 {angstrom} resolution. Its overall fold and the subunit assembly closely resemble those of DDH. Comparison of this structure and the DDH structure, available only in substrate bound form, shows the expected change of the coordination of the essential K{sup +} from hexacoordinate to heptacoordinate with the displacement of a single coordinated water by the substrate diol. In addition, there appears to be an increase in the rigidity of the K{sup +} coordination (as measured by lower B values) upon the binding of the substrate. Structural analysis of the locations of conserved residues among various GDH and DDH sequences has aided in identification of residues potentially important for substrate preference or specificity of protein-protein interactions.

  14. Substrate versatility of polyhydroxyalkanoate producing glycerol grown bacterial enrichment culture.

    PubMed

    Moralejo-Gárate, Helena; Kleerebezem, Robbert; Mosquera-Corral, Anuska; Campos, José Luis; Palmeiro-Sánchez, Tania; van Loosdrecht, Mark C M

    2014-12-01

    Waste-based polyhydroxyalkanoate (PHA) production by bacterial enrichments generally follows a three step strategy in which first the wastewater is converted into a volatile fatty acid rich stream that is subsequently used as substrate in a selector and biopolymer production units. In this work, a bacterial community with high biopolymer production capacity was enriched using glycerol, a non-fermented substrate. The substrate versatility and PHA production capacity of this community was studied using glucose, lactate, acetate and xylitol as substrate. Except for xylitol, very high PHA producing capacities were obtained. The PHA accumulation was comparable or even higher than with glycerol as substrate. This is the first study that established a high PHA content (≈70 wt%) with glucose as substrate in a microbial enrichment culture. The results presented in this study support the development of replacing pure culture based PHA production by bacterial enrichment cultures. A process where mixtures of substrates can be easily handled and the acidification step can potentially be avoided is described.

  15. Stability conditions and mechanism of cream soaps: role of glycerol.

    PubMed

    Sagitani, Hiromichi

    2014-01-01

    Fatty acids, fatty acid potassium soaps, glycerol and water are essential ingredients in the production of stable cream soaps. In this study, the behavior of these components in solution was investigated to elucidate the stability conditions and mechanism of cream soaps. It was determined that the cream soaps were a dispersion of 1:1 acid soap (1:1 molar ratio of potassium soap/fatty acid) crystals in the lamellar gel phase, which has confirmed from the phase behavior diagrams and small angle X-ray scattering data. Glycerol was crucial ingredient in the formation of the lamellar gel phase. The cleansing process of the cream soaps was also evaluated using the same diagrams. The structure of the continuous phase in cream soaps changed from lamellar gel to a micellar aqueous solution upon the addition of water. This structural change during the washing process is important in producing the foaming activity of acid soaps to wash away dirt or excess fats from the skin surface.

  16. Unfolding of the myosin head by purealin in glycerol.

    PubMed

    Takito, Jiro; Kobayashi, Jun'ichi; Nakamura, Masanori; Ohizumi, Yasushi; Nonomura, Yoshiaki

    2017-01-11

    Purealin is a small bioactive compound obtained from the marine sponge. The compound modulates various types of ATPase activity of myosin from skeletal muscle, cardiac muscle, and smooth muscle. To elucidate the structural basis of these effects of purealin on myosin ATPases, we examined the effect of purealin on the conformation of skeletal muscle myosin in aqueous solution and in glycerol. Analysis of the circular dichroism spectrum of subfragment 1, a single-headed fragment of myosin, revealed that in 10% glycerol purealin decreased the β-sheet content of S1, but in aqueous solution it had little effect on the secondary structure of S1. A myosin monomer conforms to two pear-like globular heads attached to a long tail. Electron microscopy observations with rotary shadowing revealed that purealin unfolded each globular head to an extended single strand. The tips of the unfolded strand bound each other and formed a ring in one molecule. These results suggest that binding of purealin affects the critical parameters of myosin folding.

  17. Effect of crude glycerol on pellet mill production and nursery pig growth performance.

    PubMed

    Groesbeck, C N; McKinney, L J; Derouchey, J M; Tokach, M D; Goodband, R D; Dritz, S S; Nelssen, J L; Duttlinger, A W; Fahrenholz, A C; Behnke, K C

    2008-09-01

    The objective of this study was to determine the effects of diets containing crude glycerol on pellet mill production efficiency and nursery pig growth performance. In a pilot study, increasing crude glycerol (0, 3, 6, 9, 12, and 15%) in a corn-soybean meal diet was evaluated for pellet mill production efficiency. All diets were steam conditioned to 65.5 degrees C and pelleted through a pellet mill equipped with a die that had an effective thickness of 31.8 mm and holes 3.96 mm in diameter. Each diet was replicated by manufacturing a new batch of feed 3 times. Increasing crude glycerol increased both the standard (linear and quadratic, P < 0.01) and modified (linear, P < 0.01; quadratic, P glycerol decreased (linear; P < 0.01) production rate (t/h) and production efficiency (kWh/t). In a 26-d growth assay, 182 pigs (initial BW, 11.0 +/- 1.3 kg; 5 or 6 pigs/pen) were fed 1 of 7 corn-soybean meal-based diets with no added soy oil or crude glycerol (control), the control diet with 3 or 6% added soy oil, 3 or 6% added crude glycerol, and 6 or 12% addition of a 50:50 (wt/wt) soy oil/crude glycerol blend with 5 pens/diet. The addition of crude glycerol lowered (P < 0. 01) delta temperature, amperage, motor load, and production efficiency. The addition of crude glycerol improved (P < 0.01) pellet durability compared with soy oil and the soy oil/crude glycerol blend treatments. Pigs fed increasing crude glycerol had increased (linear, P = 0.03) ADG. Average daily gain tended to increase with increasing soy oil (quadratic; P = 0.07) or the soy oil/crude glycerol blend (linear, P = 0.06). Adding crude glycerol to the diet did not affect G:F compared with the control. Gain:feed tended to increase with increasing soy oil (linear, P < 0.01; quadratic, P = 0.06) or the soy oil/crude glycerol blend (linear, P < 0.01; quadratic, P = 0.09). Nitrogen digestibility tended (P = 0

  18. Glass polymorphism in glycerol-water mixtures: II. Experimental studies.

    PubMed

    Bachler, Johannes; Fuentes-Landete, Violeta; Jahn, David A; Wong, Jessina; Giovambattista, Nicolas; Loerting, Thomas

    2016-04-28

    We report a detailed experimental study of (i) pressure-induced transformations in glycerol-water mixtures at T = 77 K and P = 0-1.8 GPa, and (ii) heating-induced transformations of glycerol-water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s(-1)-10 K h(-1)) and for the whole range of glycerol mole fractions, χ(g). Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χg ≥ 0.20), ice (χ(g) ≤ 0.32), and/or "distorted ice" (0 < χ(g) ≤ 0.38). Upon compression, we find that (a) fully vitrified samples at χ(g) ≥ 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol-water mixtures is shown to be possible only up to χ(g) ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χ(g) < 0.38, cooling leads to phase-separated samples with ice and maximally freeze-concentrated solution of χ(g) ≈ 0.38. Accordingly, in the range 0.32 < χ(g) < 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at χ(g) ≤ 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 < χ(g) ≤ 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (χ(g) ≤ 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol-water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex "phase" behavior

  19. Effects of acidified aqueous glycerol and glycerol carbonate pretreatment of rice husk on the enzymatic digestibility, structural characteristics, and bioethanol production.

    PubMed

    Ebrahimi, Majid; Villaflores, Oliver B; Ordono, Emma E; Caparanga, Alvin R

    2017-03-01

    Rice husk as an abundant biomass was used in this study, and it contained 30.1% glucan and 13.5% xylan, 22.4% lignin. The pretreated rice husk with glycerol carbonate and acidified aqueous glycerol (10% water) at 90°C and 130°C for 60min had the maximum yield of glucan digestibility which was 78.2% and 69.7% respectively, using cellulase for 72h. The simultaneous saccharification and fermentation was conducted anaerobically at 37°C with Saccharomyces cerevisiae, 5% w/v glucan and 10FPU/g glucan of cellulase. 11.58 and 8.84g/L was the highest ethanol concentration after 3days of incubation form pretreated rice husk with glycerol carbonate and acidified aqueous glycerol respectively.

  20. A multidomain enzyme, with glycerol-3-phosphate dehydrogenase and phosphatase activities, is involved in a chloroplastic pathway for glycerol synthesis in Chlamydomonas reinhardtii.

    PubMed

    Morales-Sánchez, Daniela; Kim, Yeongho; Terng, Ee Leng; Peterson, Laura; Cerutti, Heriberto

    2017-03-08

    Understanding the unique features of algal metabolism may be necessary to realize the full potential of algae as feedstock for the production of biofuels and biomaterials. Under nitrogen deprivation, the green alga C. reinhardtii showed substantial triacylglycerol (TAG) accumulation and up-regulation of a gene, GPD2, encoding a multidomain enzyme with a putative phosphoserine phosphatase (PSP) motif fused to glycerol-3-phosphate dehydrogenase (GPD) domains. Canonical GPD enzymes catalyze the synthesis of glycerol-3-phosphate (G3P) by reduction of dihydroxyacetone phosphate (DHAP). G3P forms the backbone of TAGs and membrane glycerolipids and it can be dephosphorylated to yield glycerol, an osmotic stabilizer and compatible solute under hypertonic stress. Recombinant Chlamydomonas GPD2 showed both reductase and phosphatase activities in vitro and it can work as a bifunctional enzyme capable of synthesizing glycerol directly from DHAP. In addition, GPD2 and a gene encoding glycerol kinase were up-regulated in Chlamydomonas cells exposed to high salinity. RNA-mediated silencing of GPD2 revealed that the multidomain enzyme was required for TAG accumulation under nitrogen deprivation and for glycerol synthesis under high salinity. Moreover, a GPD2-mCherry fusion protein was found to localize to the chloroplast, supporting the existence of a GPD2-dependent plastid pathway for the rapid synthesis of glycerol in response to hyperosmotic stress. We hypothesize that the reductase and phosphatase activities of PSP-GPD multidomain enzymes may be modulated by post-translational modifications/mechanisms, allowing them to synthesize primarily G3P or glycerol depending on environmental conditions and/or metabolic demands in algal species of the core Chlorophytes. This article is protected by copyright. All rights reserved.

  1. Biodegradable Composites Based on Starch/EVOH/Glycerol Blends and Coconut Fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unripe coconut fibers were used as fillers in a biodegradable polymer matrix of starch/Ethylene vinyl alcohol (EVOH)/glycerol. The effects of fiber content on the mechanical, thermal and structural properties were evaluated. The addition of coconut fiber into starch/EVOH/glycerol blends reduced the ...

  2. Enhancing effect of glycerol on the tensile properties of Bombyx mori cocoon sericin films.

    PubMed

    Zhang, Haiping; Deng, Lianxia; Yang, Mingying; Min, Sijia; Yang, Lei; Zhu, Liangjun

    2011-01-01

    An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0-40 wt% of glycerol) sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition of different concentrations of glycerol. The introduction of glycerol results in the higher amorphous structure in sericin films as evidenced by analysis of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra, thermogravimetry (TGA) and differential scanning calorimetry (DSC) curves. Scanning Electron Microscopy (SEM) observation revealed that glycerol was homogeneously blended with sericin molecules when its content was 10 wt%, while a small amount of redundant glycerol emerged on the surface of sericin films when its content was increased to 20 wt% or higher. Our results suggest that the introduction of glycerol is a novel nontoxic strategy which can improve the mechanical features of sericin-based materials and subsequently promote the feasibility of its application in tissue engineering.

  3. Transport of 3,4-dihydroxybutyl-1-phosphonate, an analogue of sn-glycerol 3-phosphate.

    PubMed Central

    Leifer, Z; Engel, R; Tropp, B E

    1977-01-01

    3,4-Dihydroxybutyl-1-phosphonate (DHBP), an analogue of glycerol 3-phosphate, is actively transported by the sn-glycerol 3-phosphate transport system of Escherichia coli strain 8. The Km for the transport of DHBP is 200 microM. PMID:400804

  4. Periplasmic protein related to the sn-glycerol-3-phosphate transport system of Escherichia coli.

    PubMed Central

    Silhavy, T J; Hartig-Beecken, I; Boos, W

    1976-01-01

    Two-dimensional gel electrophoresis of shock fluids of Escherichia coli K-12 revealed the presence of a periplasmic protein related to sn-glycerol-3-phosphate transport (GLPT) that is under the regulation of glpR, the regulatory gene of the glp regulon. Mutants selected for their resistance to phosphonomycin and found to be defective in sn-glycerol-3-phosphate transport either did not produce GLPT or produced it in reduced amounts. Other mutations exhibited no apparent effect of GLPT. Transductions of glpT+ nalA phage P1 into these mutants and selection for growth on sn-glycerol-3-phosphate revealed a 50% cotransduction frequency to nalA. Reversion of mutants taht did not produce GLPT to growth on sn-glycerol-3-phosphate resulted in strains that produce GLPT. This suggests a close relationship of GLPT to the glpT gene and to sn-glycerol-3-phosphate transport. Attempts to demonstrate binding activity of GLPT in crude shock fluid towards sn-glycerol-3-phosphate have failed so far. However, all shock fluids, independent of their GLPT content, exhibited an enzymatic activity that hydrolyzes under the conditions of the binding assay, 30 to 60% of the sn-glycerol-3-phosphate to glycerol and inorganic orthophosphate. Images PMID:770459

  5. Metabolic impact of the glycerol channels AQP7 and AQP9 in adipose tissue and liver.

    PubMed

    Lebeck, Janne

    2014-04-01

    Obesity and secondary development of type 2 diabetes (T2D) are major health care problems throughout the developed world. Accumulating evidence suggest that glycerol metabolism contributes to the pathophysiology of obesity and T2D. Glycerol is a small molecule that serves as an important intermediate between carbohydrate and lipid metabolism. It is stored primarily in adipose tissue as the backbone of triglyceride (TG) and during states of metabolic stress, such as fasting and diabetes, it is released for metabolism in other tissues. In the liver, glycerol serves as a gluconeogenic precursor and it is used for the esterification of free fatty acid into TGs. Aquaporin 7 (AQP7) in adipose tissue and AQP9 in the liver are transmembrane proteins that belong to the subset of AQPs called aquaglyceroporins. AQP7 facilitates the efflux of glycerol from adipose tissue and AQP7 deficiency has been linked to TG accumulation in adipose tissue and adult onset obesity. On the other hand, AQP9 expressed in liver facilitates the hepatic uptake of glycerol and thereby the availability of glycerol for de novo synthesis of glucose and TG that both are involved in the pathophysiology of diabetes. The aim of this review was to summarize the current knowledge on the role of the two glycerol channels in controlling glycerol metabolism in adipose tissue and liver.

  6. Production of 3-hydroxypropionic acid from glycerol by recombinant Pseudomonas denitrificans.

    PubMed

    Zhou, Shengfang; Catherine, Christy; Rathnasingh, Chelladurai; Somasundar, Ashok; Park, Sunghoon

    2013-12-01

    3-Hydroxypropionic acid (3-HP) can be produced from glycerol through two sequential enzymatic reactions that are catalyzed by a coenzyme B12 -dependent glycerol dehydratase and an NAD(P)(+) -dependent aldehyde dehydrogenase (ALDH), respectively. Pseudomonas denitrificans synthesizes coenzyme B12 under aerobic conditions, where NAD(P)(+) is regenerated efficiently. Hence, it is considered an ideal host for the production of 3-HP from glycerol under aerobic conditions. In this study, recombinant strains of P. denitrificans were developed and their potential for the production of 3-HP from glycerol was evaluated. When the enzymes, glycerol dehydratase (DhaB) and glycerol dehydratase reactivase (GdrAB), of Klebsiella pneumoniae were expressed heterologously, P. denitrificans could produce 3-HP at 37.7 mmol/L with 62% (mol/mol) yield on glycerol. Glucose was required as the carbon and energy sources for cell growth. The overexpression of heterologous ALDH was not essential; however, the titer and yield of 3-HP were improved to 54.7 mmol/L and 67% (mol/mol), respectively, when an ALDH gene (puuC) from K. pneumoniae was overexpressed. One serious drawback hindering the use of P. denitrificans as a recombinant host for 3-HP production is that it oxidizes 3-HP to malonate and utilizes 3-HP as a carbon source for growth. This is the first report on the development and use of recombinant P. denitrificans for 3-HP production from glycerol.

  7. Systemic glycerol decreases neonatal rabbit brain and cerebellar growth independent of intraventricular hemorrhage

    PubMed Central

    Traudt, Christopher M; McPherson, Ron J; Studholme, Colin; Millen, Kathleen J; Juul, Sandra E

    2014-01-01

    Background Cerebellar hypoplasia is common problem for preterm infants, and infants that suffer intraventricular hemorrhage (IVH). To evaluate the effects of IVH on cerebellar growth and development, we used a neonatal rabbit model of systemic glycerol to produce IVH. Methods New Zealand White rabbit kits were surgically delivered 2 d preterm, and treated with i.p. glycerol (3.25 to 6.5 g/kg). Controls were born at term. IVH was documented by ultrasound. Brain MRI volumes, cerebellar foliation, proliferation (Ki-67) and Purkinje cell density were done at two weeks of life. Tissue glycerol and glutathione concentrations were measured. Results Glycerol increased IVH, subarachnoid hemorrhages and mortality in a dose-dependent manner. Total cerebellar volumes, cerebellar foliation and cerebellar proliferation were decreased in a dose-dependent manner. Glycerol accumulated rapidly in blood, brain and liver and was associated with increased glutathione concentration. All of these results were independent of IVH status. Conclusions Cerebellar hypoplasia was induced after glycerol administration in a dose-dependent manner. Given rapid tissue accumulation of glycerol, dose dependent decreased brain growth and lack of IVH effect on measured outcomes we question the validity of this model as glycerol toxicity cannot be ruled out. A more physiologic model of IVH is needed. PMID:24346111

  8. Effects of glycerol on the molecular mobility and hydrogen bond network in starch matrix.

    PubMed

    Liang, Jun; Ludescher, Richard D

    2015-01-22

    The effects of glycerol on molecular mobility and hydrogen bonding network in an amorphous glassy starch matrix were studied using phosphorescence and IR spectroscopy. Amorphous potato starch films containing varying amounts of glycerol (0, 5, 10, 20 and 30 wt.%) were formulated by rapidly dehydrating aqueous potato starch gel (5%, w/v) with a corresponding content of glycerol; X-ray diffraction data confirm that the films contained negligible content of crystalline starch. Erythrosin B (Ery B) phosphorescence was used to monitor the molecular mobility of these matrices over the temperature range from 0 to 100°C. Analysis of Ery B emission peak frequency, band width and intensity decay provided information about thermally-activated modes of molecular mobility in the matrix. Dipolar relaxation around the triplet state of Ery B was enhanced by addition of glycerol and the extent of relaxation increased at low and intermediate but decreased at higher temperature. The glycerol content-dependent onset temperature for this transition was 70°C for pure starch and decreased to 40°C for a matrix with 30% glycerol. Measurements of the rate of non-radiative decay from the Ery B triplet state indicated that glycerol plasticized the starch matrix above ∼10 wt.% while acting as an antiplastizer to increase the matrix molecular mobility at lower content. These matrix properties were related to glycerol-dependent increases in hydrogen bond strength as measured by IR.

  9. Degree of branching in hyperbranched poly(glycerol-co-diacid)s synthesized in toluene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperbranched polymers were synthesized by using a Lewis acid (dibutyltin(IV)oxide) to catalyze the polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutaric acid (n=3) or azelaic acid (n=7) in toluene. These are the first examples of diacid-glycerol hyperbranc...

  10. The Lewis-acid-catalyzed synthesis of hyperbranched poly(glycerol-diacid)s in toluene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The first examples of monomeric glycerol-derived hyperbranched polyesters produced in a non-polar solvent system are reported here. The polymers were made by the Lewis acid (dibutyltin(IV)oxide)-catalyzed polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutari...

  11. Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

    EPA Science Inventory

    A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

  12. Co-digestion of sewage sludge with glycerol to boost biogas production

    SciTech Connect

    Fountoulakis, M.S.; Petousi, I.; Manios, T.

    2010-10-15

    The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 {sup o}C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106 {+-} 36 ml CH{sub 4}/d before the addition of glycerol and 2353 {+-} 94 ml CH{sub 4}/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate ({mu}{sub max}) and the saturation constant (K{sub S}) of glycerol were 0.149 {+-} 0.015 h{sup -1} and 0.276 {+-} 0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process.

  13. Study of combined effects of Glycerol and Transglutaminase on properties of gelatin films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gelatin films plasticized with different glycerol contents (0-40%) were cross-linked using transglutaminase (TGase). Unmodified films were prepared as controls. Cross-linking degree of the films decreased linearly with increasing glycerol content, resulting in an increase in water solubility. Glycer...

  14. Co-digestion of sewage sludge with glycerol to boost biogas production.

    PubMed

    Fountoulakis, M S; Petousi, I; Manios, T

    2010-10-01

    The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 degrees C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106+/-36 ml CH(4)/d before the addition of glycerol and 2353+/-94 ml CH(4)/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate (mu(max)) and the saturation constant (K(S)) of glycerol were 0.149+/-0.015 h(-1) and 0.276+/-0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process.

  15. Synthesis of biodiesel fuel additives from glycerol using green chemistry and supercritical fluids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For every 3 moles of fatty acid esters produced, 1 mole of glycerol remains, ~11% of the biodiesel volume. One new method of glycerol use could be as a biodiesel fuel additive/extender using eco-friendly heterogeneous catalysts and supercritical fluids (SFs). SFs have advantages such as greater diff...

  16. Enhancing Effect of Glycerol on the Tensile Properties of Bombyx mori Cocoon Sericin Films

    PubMed Central

    Zhang, Haiping; Deng, Lianxia; Yang, Mingying; Min, Sijia; Yang, Lei; Zhu, Liangjun

    2011-01-01

    An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0–40 wt% of glycerol) sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition of different concentrations of glycerol. The introduction of glycerol results in the higher amorphous structure in sericin films as evidenced by analysis of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra, thermogravimetry (TGA) and differential scanning calorimetry (DSC) curves. Scanning Electron Microscopy (SEM) observation revealed that glycerol was homogeneously blended with sericin molecules when its content was 10 wt%, while a small amount of redundant glycerol emerged on the surface of sericin films when its content was increased to 20 wt% or higher. Our results suggest that the introduction of glycerol is a novel nontoxic strategy which can improve the mechanical features of sericin-based materials and subsequently promote the feasibility of its application in tissue engineering. PMID:21686177

  17. Microstructure and molecular interaction in glycerol plasticized chitosan/poly(vinyl alcohol) blending films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly (vinyl alcohol) (PVA)/chitosan (CS) blended films plasticized by glycerol were investigated using mechanical testing, atomic force microscopy (AFM), differential scanning calorimetry (DSC) and FTIR spectroscopy, with primary emphasis on the effects of the glycerol content and the molecular weig...

  18. Activation of glycerol metabolism in Xanthomonas campestris by adaptive evolution to produce a high-transparency and low-viscosity xanthan gum from glycerol.

    PubMed

    Wang, Zichao; Wu, Jianrong; Zhu, Li; Zhan, Xiaobei

    2016-07-01

    Many studies have focused on using crude glycerol from biodiesel to obtain valuable products, but few of these studies have focused on obtaining polysaccharides. A mutant strain of Xanthomonas campestris CCTCC M2015714 that could use glycerol to produce high-transparency and low-viscosity xanthan gum was obtained by adaptive evolution, and the yield of xanthan gum reached 11.0g/L. We found that transcriptional levels of genes related to glycerol metabolism (glpF, glpK, glpD, and fbp) in the mutant strain were all higher than those from the parent strain. Using 5g/L sucrose or glucose as starter substrate, cell growth time decreased from 36h to 24h and xanthan gum yield increased. Moreover, the mutant strain can tolerate high titer glycerol, and its activity was not affected by the impurities in crude glycerol. All these results proved that crude glycerol from biodiesel industries can be used for xanthan gum production.

  19. Distribution of Glycerol Diakyl Glycerol Tetraethers in Surface Soil and Crater Lake Sediments from Mount Kenya, East Africa

    NASA Astrophysics Data System (ADS)

    Omuombo, C.; Huguet, A.; Olago, D.; Williamson, D.

    2013-12-01

    Glycerol diakyl glycerol tetraethers (GDGTs), a palaeoclimate proxy based on the relative abundance of lipids produced by archaea and bacteria, is gaining wide acceptance for the determination of past temperature and pH conditions. This study looks at the spatial distribution and abundance of GDGTs in soil and sediment samples along an altitudinal transect from 3 crater lakes of Mt. Kenya (Lake Nkunga, Sacred Lake and Lake Rutundu) ranging in elevation from 1700m - 3080m above sea level. GDGTs were extracted with solvents and then analysed using high performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS). Mean annual air temperature and pH were estimated based on the relative abundance of the different branched GDGTs, i.e. on the MBT (Methylation index of Branched Tetraethers) and CBT (Cyclization ratio of Branched Tetraethers) indices. Substantial amount of GDGTs were detected in both soil and sediment samples. In addition, branched GDGT distribution was observed to vary with altitude. These results highlight the importance of quantifying the branched GDGTs to understand the environmental parameters controlling the distribution of these lipids. The MBT/CBT proxy is a promising tool to infer palaeotemperatures and characterize the climate events of the past millennia in equatorial east Africa.

  20. The role of glycerol in the pathogenic lifestyle of the rice blast fungus Magnaporthe oryzae.

    PubMed

    Foster, Andrew J; Ryder, Lauren S; Kershaw, Michael J; Talbot, Nicholas J

    2017-03-01

    The rice blast fungus Magnaporthe oryzae elaborates a specialized cell called an appressorium, which is used to breach the tough outer cuticle of a rice leaf, enabling the fungus entry to host plant cells. The appressorium generates enormous turgor by accumulating glycerol to very high concentrations within the cell. Glycerol accumulation and melanization of the appressorium cell wall collectively drive turgor-mediated penetration of the rice leaf. In this review, we discuss the potential metabolic sources of glycerol in the rice blast fungus and how appressorium turgor is focused as physical force at the base of the infection cell, leading to the formation of a rigid penetration peg. We review recent studies of M. oryzae and other relevant appressorium-forming fungi which shed light on how glycerol is synthesized and how appressorium turgor is regulated. Finally, we provide some questions to guide avenues of future research that will be important in fully understanding the role of glycerol in rice blast disease.

  1. Lipase-catalyzed simultaneous biosynthesis of biodiesel and glycerol carbonate from corn oil in dimethyl carbonate.

    PubMed

    Min, Ji Young; Lee, Eun Yeol

    2011-09-01

    Biodiesel [fatty acid methyl esters (FAMEs)] and glycerol carbonate were synthesized from corn oil and dimethyl carbonate (DMC) via transesterification using lipase (Novozyme 435) in solvent-free reaction in which excess DMC was used as the substrate and reaction medium. Glycerol carbonate was also simultaneously formed from DMC and glycerol. Conversions of FAMEs and glycerol carbonate were examined in batch reactions. The FAMEs and glycerol carbonate reached 94 and 62.5% from oil and DMC (molar ratio of 1:10) with 0.2% (v/v) water and 10% (w/w) Novozyme 435 (based on oil weight) at 60 °C. When Novozyme 435 was washed with acetone after each reaction, more than 80% activity still remained after seven recycling.

  2. Dietary tools to modulate glycogen storage in gilthead seabream muscle: glycerol supplementation.

    PubMed

    Silva, Tomé S; Matos, Elisabete; Cordeiro, Odete D; Colen, Rita; Wulff, Tune; Sampaio, Eduardo; Sousa, Vera; Valente, Luisa M P; Gonçalves, Amparo; Silva, Joana M G; Bandarra, Narcisa; Nunes, Maria Leonor; Dinis, Maria Teresa; Dias, Jorge; Jessen, Flemming; Rodrigues, Pedro M

    2012-10-24

    The quality and shelf life of fish meat products depend on the skeletal muscle's energetic state at slaughter, as meat decomposition processes can be exacerbated by energy depletion. In this study, we tested dietary glycerol as a way of replenishing muscle glycogen reserves of farmed gilthead seabream. Two diets were tested in duplicate (n = 42/tank). Results show 5% inclusion of crude glycerol in gilthead seabream diets induces increased muscle glycogen, ATP levels and firmness, with no deleterious effects in terms of growth, proximate composition, fatty acid profile, oxidative state, and organoleptic properties (aroma and color). Proteomic analysis showed a low impact of glycerol-supplementation on muscle metabolism, with most changes probably reflecting increased stress coping capacity in glycerol-fed fish. This suggests inclusion of crude glycerol in gilthead seabream diets (particularly in the finishing phase) seems like a viable strategy to increase glycogen deposition in muscle without negatively impacting fish welfare and quality.

  3. Direct nonchromatographic assay for 1-acyl-sn-glycerol-3-phosphate acyltransferase

    SciTech Connect

    Rajasekharan, R.; Ray, T.K.; Cronan, J.E. Jr.

    1988-09-01

    1-Acyl-sn-glycerol-3-phosphate acyltransferase (also called lysophosphatidic acid acyltransferase) which catalyzes the acylation of 1-acyl-sn-glycerol-3-phosphate to phosphatidic acid is generally assayed by the use of a radioactive substrate followed by a time-consuming chromatographic separation of substrate and product. We report a direct and highly sensitive nonchromatographic assay for this enzyme based on the ability of Escherichia coli alkaline phosphatase to dephosphorylate 1-acyl-sn-glycerol-3-phosphate but not phosphatidic acid. This selective hydrolysis coupled with the use of /sup 32/P-labeled 1-acyl-sn-glycerol-3-phosphate as substrate permits measurement of the product, /sup 32/P-labeled phosphatidic acid by solvent extraction or precipitation. We also report a series of enzymatic reactions for the efficient conversion of /sup 32/Pi to /sup 32/P-labeled 1-acyl-sn-glycerol-3-phosphate.

  4. Fermentation of glycerol and production of valuable chemical and biofuel molecules.

    PubMed

    Mattam, Anu Jose; Clomburg, James M; Gonzalez, Ramon; Yazdani, Syed Shams

    2013-06-01

    Glycerol has attracted the attention of scientific and industrial communities due to its generation in bulk quantities as a byproduct of biofuel industries. With the rapid growth of these industries in recent years, glycerol is frequently treated as a very low-value byproduct or even a waste product with a disposal cost associated to it. Glycerol is not only abundant and inexpensive but also can generate more reducing equivalents than glucose or xylose. This unique characteristic of glycerol offers a tremendous opportunity for its biological conversion to valuable products at higher yield. This review focuses on research efforts to utilize glycerol as a carbon source for the production of a variety of fuels and chemicals by both native and metabolically engineered microorganisms.

  5. Efficient production of dihydroxyacetone from biodiesel-derived crude glycerol by newly isolated Gluconobacter frateurii.

    PubMed

    Liu, Yu-Peng; Sun, Yang; Tan, Cong; Li, Hua; Zheng, Xiao-Juan; Jin, Kui-Qi; Wang, Gang

    2013-08-01

    The efficient production of dihydroxyacetone (DHA) on biodiesel-derived glycerol based media was developed. A newly isolated strain, Gluconobacter frateurii CGMCC 5397, could convert crude glycerol to DHA with high yield and productivity. In shake-flask fermentation, the DHA concentration of 73.1 gl(-1) was attained at 48 h using an optimum medium containing biodiesel-derived crude glycerol. When fed-batch fermentation was carried out in a 7-l stirred bioreactor with crude glycerol, the DHA concentration, productivity, and yield were 125.8 gl(-1), 2.6 gl(-1)h(-1), and 90.5% at 48 h, respectively. This study suggests that the inexpensive biodiesel-derived crude glycerol could be utilized for efficient production of DHA by G. frateurii.

  6. Salty glycerol versus salty water surface organization: bromide and iodide surface propensities.

    PubMed

    Huang, Zishuai; Hua, Wei; Verreault, Dominique; Allen, Heather C

    2013-07-25

    Salty NaBr and NaI glycerol solution interfaces are examined in the OH stretching region using broadband vibrational sum frequency generation (VSFG) spectroscopy. Raman and infrared (IR) spectroscopy are used to further understand the VSFG spectroscopic signature. The VSFG spectra of salty glycerol solutions reveal that bromide and iodide anions perturb the interfacial glycerol organization in a manner similar as that found in aqueous halide salt solutions, thus confirming the presence of bromide and iodide anions at the glycerol surface. Surface tension measurements are consistent with the surface propensity suggested by the VSFG data and also show that the surface excess increases with increasing salt concentration, similar to that of water. In addition, iodide is shown to have more surface prevalence than bromide, as has also been determined from aqueous solutions. These results suggest that glycerol behaves similarly to water with respect to surface activity and solvation of halide anions at its air/liquid interface.

  7. Dietary glycerol for quail: association between productive performance and COX III mRNA expression.

    PubMed

    Silva, S C C; Gasparino, E; Batista, E; Tanamati, F; Vesco, A P D; Lala, B; de Oliveira, D P

    2016-05-25

    This study was carry out to evaluate mRNA expression of mitochondrial cytochrome c oxidase III in the Pectoralis superficialis muscle of 28-day-old quails fed diets containing 0, 8, and 12% glycerol. Total RNA was extracted (N = 10) and cDNA was amplified using specifics primers for qRT-PCR. Feed efficiency and feed intake were evaluated. COX III mRNA expression in breast muscle was higher in the group fed with 12% glycerol (0.863 AU); no differences were observed in the expression of this gene between the muscle of animals fed diets without glycerol (0.357 AU) and 8% glycerol (0.415 AU). Quails that showed greater COX III mRNA expression also showed the lowest feed efficiency. These results show that there is a difference in COX III mRNA expression in breast muscle of 28-day-old quail fed diets different concentrations of glycerol.

  8. Microbial conversion of glycerol to 1,3-propanediol and related compounds

    SciTech Connect

    Cameron, D.C.; Held, A.M.; Zhu, Mei-Ying

    1995-12-01

    Glycerol is a co-product of the conversion of vegetable oils and animal fats to soap, fatty acids, fatty acid esters and biodiesel fuel. We have investigated the use of both native and recombinant microorganisms for the conversion of glycerol to more valuable products. Fed-batch fermentations of glycerol by Klebsiella pneumoniae gave over 50 g/L of 1,3-propanediol (1,3-PD, trimethylene glycol) with high volumetric productivity. Escherichia coli containing genes for glycerol dehydratase and 1,3-PD oxidoreductase from K. pneumoniae also gave 1,3-PD from glycerol, but at a lower level than the native organism. Experiments with the recombinant E. coli have provided insights into ways to improve 1,3-PD production in both the recombinant and native organism and to modify the pathway for the production of compounds such as 3-hydroxypropionaldehyde and dihydroxyacetone.

  9. Ionic mobility and dielectric relaxation in supercooled liquid KCl-glycerol solutions

    NASA Astrophysics Data System (ADS)

    Champeney, D. C.; Ould Kaddour, F.

    Measurements of the electrical conductivities of liquid and supercooled liquid KCl-glycerol solutions between + 50·6°C and -89·1°C are described. Time domain measurements of dielectric relaxation in pure glycerol between -78·1°C and -91·0°C, and in KCl-glycerol solutions between -77·5°C and -89·1°C are also described. Empirical equations are presented which in each case describe the non-Arrhenius temperature dependence over more than 12 decades in value with a r.m.s. deviation of less than 15 per cent. A 'power law' fit is found to be slightly better than a 'Vogel-Tammann-Fulcher' fit in each case. The temperature dependence of Walden product for KCl-glycerol solutions is discussed, and the relaxation data for pure glycerol is discussed in the light of the Kauzmann paradox.

  10. Pilot Plant Glycerol Production with a Slow-Feed Osmophilic Yeast Fermentation

    PubMed Central

    Button, D. K.; Garver, J. C.; Hajny, G. J.

    1966-01-01

    A slow feed batch fermentation is described for the production of glycerol from sugar. The conversion efficiency was approximately 1 mole of glycerol produced per mole of glucose utilized after the cell growth phase. The glycerol production phase was extended several-fold by periodic glucose addition. The yeast cell count remained constant during this time as limited by phosphate, a deficiency required for an efficient glycerol fermentation. A small amount of phosphate was supplied during the extended fermentation, maintaining an active culture, by the normal autolysis of spent cells. Interfering or inhibitory by-products did not accumulate, and the osmophilic yeasts are tolerant of high glycerol concentrations. These factors combined to allow a particularly efficient fermentation well suited to product enrichment by supplying large quantities of substrate over an extended period. PMID:6006420

  11. Moisturizing Effects of Diglycerol Combined with Glycerol on Human Stratum Corneum.

    PubMed

    Tomiie, Ai; Shinozaki, Masami; Yamada, Takeshi; Kuriyama, Juhei

    2016-08-01

    The water content of the stratum corneum was measured to investigate the skin-moisturizing property of diglycerol in water and in a lotion. The water content of the stratum corneum, to which the diglycerol solution was applied, was lower than that of the glycerol solution for 8 h. However, skin treated with diglycerol in combination with glycerol solution maintained a higher capacitance level compared with that of glycerol solution alone after 8 h. Moreover, the long-term moisturizing effect of the stratum corneum prominently appeared when diglycerol was formulated to the lotion containing glycerol and 1,3-butylene glycol. These studies suggest that diglycerol in combination with glycerol has a long-term moisturizing effect on human skin.

  12. Inclusion of glycerol in forage diets increases methane production in a rumen simulation technique system.

    PubMed

    Avila-Stagno, Jorge; Chaves, Alexandre V; Ribeiro, Gabriel O; Ungerfeld, Emilio M; McAllister, Tim A

    2014-03-14

    We hypothesised that the inclusion of glycerol in the forage diets of ruminants would increase the proportion of propionate produced and thereby decrease in vitro CH₄ production. This hypothesis was examined in the present study using a semi-continuous fermentation system (rumen simulation technique) fed a brome hay (8·5 g) and maize silage (1·5 g) diet with increasing concentrations (0, 50, 100 and 150 g/kg DM) of glycerol substituted for maize silage. Glycerol linearly increased total volatile fatty acids production (P<0·001). Acetate production was quadratically affected (P=0·023) and propionate and butyrate production was linearly increased (P<0·001). Glycerol linearly increased (P=0·011) DM disappearance from hay and silage. Crude protein disappearance from hay was not affected (P=0·789), but that from silage was linearly increased (P<0·001) with increasing glycerol concentrations. Neutral-detergent fibre (P=0·040) and acid-detergent fibre (P=0·031) disappearance from hay and silage was linearly increased by glycerol. Total gas production tended to increase linearly (P=0·061) and CH₄ concentration in gas was linearly increased (P<0·001) by glycerol, resulting in a linear increase (P<0·001) in mg CH₄/g DM digested. Our hypothesis was rejected as increasing concentrations of glycerol in a forage diet linearly increased CH₄ production in semi-continuous fermenters, despite the increases in the concentrations of propionate. In conclusion, this apparent discrepancy is due to the more reduced state of glycerol when compared with carbohydrates, which implies that there is no net incorporation of electrons when glycerol is metabolised to propionate.

  13. Short communication: Regulation of hepatic gluconeogenic enzymes by dietary glycerol in transition dairy cows.

    PubMed

    White, H M; Carvalho, E R; Koser, S L; Schmelz-Roberts, N S; Pezzanite, L M; Slabaugh, A C; Doane, P H; Donkin, S S

    2016-01-01

    Nutritional status and glucose precursors are known regulators of gluconeogenic gene expression. Glycerol can replace corn in diets fed to dairy cows and use of glycerol is linked to increased rumen propionate production. The effect of dietary glycerol on the regulation of gluconeogenic enzymes is unknown. The objective of this study was to examine the effect of glycerol on expression of pyruvate carboxylase (PC), cytosolic and mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-C and PEPCK-M), and glucose-6-phosphatase. Twenty-six multiparous Holstein cows were fed either a control diet or a diet where high-moisture corn was replaced by glycerol from -28 through +56 d relative to calving (DRTC). Liver tissue was collected via percutaneous liver biopsy at -28, -14, +1, +14, +28, and +56 DRTC for RNA analysis. Expression of PC mRNA increased 6-fold at +1 and 4-fold at +14 DRTC relative to precalving levels. Dietary glycerol did not alter expression of PC mRNA expression. Expression of PEPCK-C increased 2.5-fold at +14 and 3-fold at +28 DRTC compared with +1 DRTC. Overall, dietary glycerol increased PEPCK-C expression compared with that of cows fed control diets. The ratio of PC to PEPCK-C was increased 6.3-fold at +1 DRTC compared with precalving and tended to be decreased in cows fed glycerol. We detected no effect of diet or DRTC on PEPCK-M or glucose-6-phosphatase mRNA, and there were no interactions of dietary treatment and DRTC for any transcript measured. Substituting corn with glycerol increased the expression of PEPCK-C mRNA during transition to lactation and suggests that dietary energy source alters hepatic expression. The observed increase in PEPCK-C expression with glycerol feeding may indicate regulation of hepatic gene expression by changes in rumen propionate production.

  14. Enhancing visible light photocatalytic activity of direct Z-scheme SnS{sub 2}/Ag{sub 3}PO{sub 4} heterojunction photocatalysts

    SciTech Connect

    Luo, Jin Zhou, Xiaosong; Ma, Lin; Xu, Limei; Xu, Xuyao; Du, Zhihua; Zhang, Jinquan

    2016-09-15

    Highlights: • Novel direct Z-scheme SnS{sub 2}/Ag{sub 3}PO{sub 4} heterojunction photocatalysts are synthesized. • SnS{sub 2}/Ag{sub 3}PO{sub 4} exhibits much higher photocatalytic activity than pure SnS{sub 2} and Ag{sub 3}PO{sub 4}. • A possible photocatalytic mechanism was discussed in detail. - Abstract: Novel direct Z-scheme SnS{sub 2}/Ag{sub 3}PO{sub 4} heterojunction photocatalysts were successfully fabricated with SnS{sub 2} nanoplates hybridized by Ag{sub 3}PO{sub 4} nanoparticals via a facile hydrothermal and precipitation method and applied for the photocatalytic degradation of methyl orange in aqueous solution under visible light irradiation (λ > 420 nm). It was found that the photocatalytic performance of the SnS{sub 2} (2.0 wt%)/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with 2.0 wt% SnS{sub 2} content was much higher than that of individual SnS{sub 2} and Ag{sub 3}PO{sub 4}. The enhanced photocatalytic activity could be ascribed to the efficient separation of photogenerated electrons and holes through the formation of direct Z-scheme system composed of SnS{sub 2} and Ag{sub 3}PO{sub 4}. Furthermore, the recycling experiments revealed that the photocorrosion behavior of Ag{sub 3}PO{sub 4} was strongly inhibited by SnS{sub 2}, it may be due to the photogenerated electrons of Ag{sub 3}PO{sub 4} would be quickly combined with the photogenerated holes of SnS{sub 2}. This work will be useful for the design of other direct Z-scheme visible-light-driven photocatalytic systems for application in energy conversion and environmental remediation.

  15. Local and Cooperative Jahn-Teller Effect and Resultant Magnetic Properties of M2AgF4 (M = Na-Cs) Phases.

    PubMed

    Kurzydłowski, Dominik; Jaroń, Tomasz; Ozarowski, Andrew; Hill, Stephen; Jagličić, Zvonko; Filinchuk, Yaroslav; Mazej, Zoran; Grochala, Wojciech

    2016-11-07

    The crystal structure, magnetic properties, heat capacity, and Raman spectra of double-perovskite M2AgF4 (M = K, K3/4Rb1/4, K1/2Rb1/2, K1/4Rb3/4, and Rb) phases have been examined, adding to the body of previous results for the M = Na, Cs derivatives. The results suggest that double-perovskite K2AgF4 adopts a disordered orthorhombic Bmab structure with an antiferrodistortive arrangement of the elongated and tilted [AgF6] octahedra rather than the structure with the ferrodistortive arrangement of compressed octahedra, as suggested previously (Mazej, Z.; Goreshnik, E.; Jagličić, Z.; Gaweł, B.; Łasocha, W.; Grzybowska, D.; Jaroń, T.; Kurzydłowski, D.; Malinowski, P. J.; Koźmiński, W.; Szydłowska, J.; Leszczyński, P. J.; Grochala, W. KAgF3, K2AgF4 and K3Ag2F7: important steps towards a layered antiferromagnetic fluoroargentate(II). CrystEngComm 2009, 11, 1702-1710). A re-examination of the previously collected single-crystal X-ray diffraction data confirms the current structure assignment, and it is also in agreement with recent theoretical calculations. High-field electron paramagnetic resonance spectra reaffirm the presence of elongated [AgF6] octahedra in the crystal structure of all M2AgF4 phases studied. The local structure of the M = K derivative is most complex, with regions of the sample that are quite orthorhombically distorted, whereas other regions more closely resemble the tetragonal phase. The mixed-cation K/Rb phases are also inhomogeneous, containing regions of the pure K compound and regions of another high-symmetry phase (likely tetragonal) of a mixed (Rb-richer) compound with unknown composition. The temperature-resolved phase diagram of all K/Rb phases has been established and positioned within the entire M = Na, K, Rb, Cs series.

  16. Compound heterozygote for lipoprotein lipase deficiency: Ser----Thr244 and transition in 3' splice site of intron 2 (AG----AA) in the lipoprotein lipase gene.

    PubMed Central

    Hata, A; Emi, M; Luc, G; Basdevant, A; Gambert, P; Iverius, P H; Lalouel, J M

    1990-01-01

    Cloning and sequencing of translated exons and intron-exon boundaries of the lipoprotein lipase gene in a patient of French descent who has the chylomicronemia syndrome revealed that he was a compound heterozygote for two nucleotide substitutions. One (TCC----ACC) leads to an amino acid substitution (Ser----Thr244), while the other alters the 3' splice site of intron 2 (AG----AA). The functional significance of the Thr244 amino acid substitution was established by in vitro expression in cultured mammalian cells. Images Figure 1 Figure 2 PMID:2121025

  17. Maintaining a glycerolized skin bank--a practical approach.

    PubMed

    Vuola, J; Pipping, D

    2002-10-01

    The Helsinki Burn Unit admits around 120-140 patients a year and, of these, 20-30 need intensive care. Before 1995, fresh, non-tested cadaver skin was used to cover widely meshed autografts in large burns. In 1995, we founded a skin bank to avoid the problems encountered in the use of fresh cadaver skin: contamination by viruses or bacteria, shortage of available skin, the occasionally poor quality of the cadaver skin, and the inconvenience of harvesting skin in the mortuary. Crucial to the work of the Skin Bank has been cooperation with the Transplantation Unit of our hospital. This reduces paperwork and guarantees the quality of the donors. It also enables us to harvest skin only from tested multiorgan donors in an operating theater setting. Also important is a well organized team to ensure the procurement of a sufficient amount of good-quality allografts. This requirement raises the otherwise low costs of a glycerolized skin bank.

  18. Complex Glycerol Kinase Deficiency and Adrenocortical Insufficiency in Two Neonates

    PubMed Central

    Korkut, Sabriye; Baştuğ, Osman; Raygada, Margarita; Hatipoğlu, Nihal; Kurtoğlu, Selim; Kendirci, Mustafa; Lyssikatos, Charalampos; Stratakis, Constantine A.

    2016-01-01

    Contiguous gene deletions of chromosome Xp21 can lead to glycerol kinase deficiency and severe adrenocortical insufficiency (AI) in a male newborn among other problems. We describe our experience with two such patients who presented with dysmorphic facies, AI, and pseudo-hypertriglyceridemia. Both infants had normal serum 17-hidroxyprogesterone levels, and adrenal glands could not be observed with ultrasonography. Creatine kinase and triglyceride levels were measured to elucidate the etiology of adrenal hypoplasia and were above normal limits in both cases. Both patients required steroid and salt supplementation. They were both found to have Xp21.2 deletions (DMD, NR0B1, GK, IL1RAPL1). We conclude that AI in the context of other genetic abnormalities should prompt chromosomal investigations in the absence of another unifying explanation. PMID:27087023

  19. Complex Glycerol Kinase Deficiency and Adrenocortical Insufficiency in Two Neonates.

    PubMed

    Korkut, Sabriye; Baştuğ, Osman; Raygada, Margarita; Hatipoğlu, Nihal; Kurtoğlu, Selim; Kendirci, Mustafa; Lyssikatos, Charalampos; Stratakis, Constantine A

    2016-12-01

    Contiguous gene deletions of chromosome Xp21 can lead to glycerol kinase deficiency and severe adrenocortical insufficiency (AI) in a male newborn among other problems. We describe our experience with two such patients who presented with dysmorphic facies, AI, and pseudo-hypertriglyceridemia. Both infants had normal serum 17-hidroxyprogesterone levels, and adrenal glands could not be observed with ultrasonography. Creatine kinase and triglyceride levels were measured to elucidate the etiology of adrenal hypoplasia and were above normal limits in both cases. Both patients required steroid and salt supplementation. They were both found to have Xp21.2 deletions (DMD, NR0B1, GK, IL1RAPL1). We conclude that AI in the context of other genetic abnormalities should prompt chromosomal investigations in the absence of another unifying explanation.

  20. Glycerol as Precursor of Organoselanyl and Organotellanyl Alkynes.

    PubMed

    Lenardão, Eder J; Borges, Elton L; Stach, Guilherme; Soares, Liane K; Alves, Diego; Schumacher, Ricardo F; Bagnoli, Luana; Marini, Francesca; Perin, Gelson

    2017-03-02

    Herein we describe the synthesis of organoselanyl and organotellanyl alkynes by the addition of lithium alkynylchalcogenolate (Se and Te) to tosyl solketal, easily obtained from glycerol. The alkynylchalcogenolate anions were generated in situ and added to tosyl solketal in short reaction times, furnishing in all cases the respective products of substitution in good yields. Some of the prepared compounds were deprotected using an acidic resin to afford new water-soluble 3-organotellanylpropane-1,2-diols. The synthetic versatility of the new chalcogenyl alkynes was demonstrated in the iodocyclization of 2,2-dimethyl-1,3-dioxolanylmethyl(2-methoxyphenylethynyl)selane 3f, which afforded 3-iodo-2-(2,2-dimethyl-1,3-dioxolanylmethyl) selenanylbenzo[b]furan in 85% yield, opening a new way to access water-soluble Se-functionalized benzo[b]furanes.

  1. Metabolism of glycerol, glucose, and lactate in the citric acid cycle prior to incorporation into hepatic acylglycerols.

    PubMed

    Jin, Eunsook S; Sherry, A Dean; Malloy, Craig R

    2013-05-17

    During hepatic lipogenesis, the glycerol backbone of acylglycerols originates from one of three sources: glucose, glycerol, or substrates passing through the citric acid cycle via glyceroneogenesis. The relative contribution of each substrate source to glycerol in rat liver acylglycerols was determined using (13)C-enriched substrates and NMR. Animals received a fixed mixture of glucose, glycerol, and lactate; one group received [U-(13)C6]glucose, another received [U-(13)C3]glycerol, and the third received [U-(13)C3]lactate. After 3 h, the livers were harvested to extract fats, and the glycerol moiety from hydrolyzed acylglycerols was analyzed by (13)C NMR. In either fed or fasted animals, glucose and glycerol provided the majority of the glycerol backbone carbons, whereas the contribution of lactate was small. In fed animals, glucose contributed >50% of the total newly synthesized glycerol backbone, and 35% of this contribution occurred after glucose had passed through the citric acid cycle. By comparison, the glycerol contribution was ~40%, and of this, 17% of the exogenous glycerol passed first through the cycle. In fasted animals, exogenous glycerol became the major contributor to acylglycerols. The contribution from exogenous lactate did increase in fasted animals, but its overall contribution remained small. The contributions of glucose and glycerol that had passed through the citric acid cycle first increased in fasted animals from 35 to 71% for glucose and from 17 to 24% for glycerol. Thus, a substantial fraction from both substrate sources passed through the cycle prior to incorporation into the glycerol moiety of acylglycerols in the liver.

  2. Hydrogenolysis of Glycerol to 1,2-Propanediol Over Clay Based Catalysts.

    PubMed

    Lee, Sang-Yong; Jung, Jae-Sun; Yang, Eun-Hyeok; Lee, Kwan-Young; Moon, Dong Ju

    2015-11-01

    1,2-propanediol (1,2-PDO) is one of the promising product among the valuable products derived from glycerol and it can be obtained by the catalytic hydrogenolysis of glycerol. Copper-supported clay-based catalysts were prepared with different pore sizes using various ratios of kaolin, Mg, and Al by coprecipitation and applied in the selective hydrogenolysis of glycerol to 1,2-PDO. In recent research, variations of pore volume and pore size could affect the diffusion of reagents within the catalyst due to the collision between reagents or pore wall and reagents. It changes selectivities of each product in hydrogenolysis of glycerol reaction. The physico-chemical properties of the catalysts were analyzed by XRD, N2 physisorption, TPR, CO2-TPD, SEM, and a mercury porosimeter. The Cu/TALCITE 4 catalyst showed 98% 1,2-PDO selectivity with 65% glycerol conversion under the optimized condition of 190 degrees C, 25 bar, and 20 wt% glycerol aqueous solution. It was found that the basic strength and meso-macro pore structure of the catalysts play an important role in glycerol conversion and 1,2-PDO selectivity.

  3. Metabolic effects of glycerol supplementation and aerobic physical training on Wistar rats.

    PubMed

    Andrade, Eric Francelino; Lobato, Raquel Vieira; Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Gomes, Núbia Ferreira; Alvarenga, Renata Ribeiro; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Pereira, Luciano José

    2014-09-01

    We evaluated the effects of oral glycerol supplementation on trained rats fed a normal diet. Wistar rats were distributed among 6 groups in a completely randomized 2 × 3 factorial design. The animals were subjected to 6 weeks of aerobic training. In the last 4 weeks, the animals' diet was supplemented with saline, glucose, or glycerol. Data were subjected to one-way analysis of variance (ANOVA) followed by a Student-Newmann-Keuls test, with values for P < 0.05 considered statistically significant. The change in body mass was lower in the trained groups, and their food and water consumption were higher. Glycerol supplementation resulted in an increase in the levels of triacylglycerol (TAG) and total cholesterol, as well as in the area and diameter of adipocytes. When associated with training, these parameters were similar to those of other trained groups. Levels of low-density lipoprotein + very-low-density lipoprotein cholesterol decreased in the trained animals that received glycerol compared with the non-trained ones. Glycerol consumption caused a reduction in food intake and increased the villous:crypt (V:C) ratio. No changes in glycemia, high density lipoproteins, or density of adipocytes were observed. Supplementation with glycerol together with aerobic physical training promoted beneficial metabolic effects. However, in non-trained rats glycerol increased the diameter and area of adipocytes, as well as the levels of TAG and total cholesterol.

  4. Trehalose in glycerol-free freezing extender enhances post-thaw survival of boar spermatozoa

    PubMed Central

    ATHURUPANA, Rukmali; TAKAHASHI, Daisen; IOKI, Sumire; FUNAHASHI, Hiroaki

    2015-01-01

    Cryopreservation of boar semen is still considered suboptimal due to lower fertility as compared with fresh samples when glycerol, a permeating cryoprotectant, is used. Trehalose is a non-permeable cryoprotectant and nonreducing disaccharide known to stabilize proteins and biologic membranes. The aim of this study was to evaluate the cryosurvival and in vitro penetrability of boar spermatozoa when glycerol was replaced with trehalose in a freezing extender. Ejaculated Berkshire semen samples were diluted in egg yolk-based freezing extender containing glycerol (100 mM) or trehalose (0, 50, 100, 150, 200 and 250 mM) and cryopreserved using a straw freezing procedure. Thawed samples were analyzed for motility, viability, mitochondrial membrane potential (MMP), and acrosome integrity. In experiment 2, penetrability of spermatozoa cryopreserved with 100 mM glycerol or trehalose was examined. Replacement of cryoprotectant glycerol (100 mM) with trehalose had no effect on sperm viability, but replacing it with 100 mM trehalose improved motility, MMP and acrosome integrity significantly. Sperm motility and MMP were considerably higher in 100 mM trehalose, whereas the acrosome integrity was substantially higher in 100–250 mM trehalose. The in vitro penetration rate was also significantly higher in spermatozoa cryopreserved with trehalose (61.3%) than in those cryopreserved with glycerol (43.6%). In conclusion, 100 mM non-permeable trehalose can be used to replace glycerol, a permeating cryoprotectant, for maintenance of better post-thaw quality of boar spermatozoa. PMID:25754239

  5. Theoretical investigation of the interaction of glycerol with aluminum and magnesium phthalocyanines.

    PubMed

    Silva, V H C; Camargo, L T F M; Napolitano, H B; Pérez, C N; Camargo, A J

    2010-09-01

    Glycerol is a byproduct produced in great quantity by biodiesel industries in transesterification reactions. Finding new applications for glycerol is a current concern of many research groups around the world. This work focuses on a theoretical investigation, at the B3LYP/6-31G* level of theory, into the possibility of using aluminum phthalocyanine (AlPc) and magnesium phthalocyanine (MgPc) in the modelling of catalysts to convert glycerol into alcohol, which has wider industrial applicability. According to our calculations there are strong interactions between the O-terminus of glycerol and the central metal atom of AlPc and MgPc. By applying the Fukui function, HSAB theory and analysis of the frontier molecular orbital, it was possible to explain the way in which glycerol interacts with AlPc and MgPc. As a result of these interactions, there is a considerable change in both electronic and geometric parameters of glycerol, which can be used in designing new strategies to convert glycerol into alcohol.

  6. Application of Glycerol for Induced Powdery Mildew Resistance in Triticum aestivum L.

    PubMed Central

    Li, Yinghui; Song, Na; Zhao, Chuanzhi; Li, Feng; Geng, Miaomiao; Wang, Yuhui; Liu, Wanhui; Xie, Chaojie; Sun, Qixin

    2016-01-01

    Previous work has demonstrated that glycerol-3-phosphate (G3P) and oleic acid (18:1) are two important signal molecules associated with plant resistance to fungi. In this article, we provide evidence that a 3% glycerol spray application 1–2 days before powdery mildew infection and subsequent applications once every 4 days was sufficient to stimulate the plant defense responses without causing any significant damage to wheat leaves. We found that G3P and oleic acid levels were markedly induced by powdery mildew infection. In addition, TaGLI1 (encoding a glycerol kinase) and TaSSI2 (encoding a stearoylacyl carrier protein fatty acid desaturase), two genes associated with the glycerol and fatty acid (FA) pathways, respectively, were induced by powdery mildew infection, and their promoter regions contain some fungal response elements. Moreover, exogenous application of glycerol increased the G3P level and decreased the level of oleic acid (18:1). Glycerol application induced the expression of pathogenesis-related (PR) genes (TaPR-1, TaPR-2, TaPR-3, TaPR-4, and TaPR-5), induced the generation of reactive oxygen species (ROS) before powdery mildew infection, and induced salicylic acid (SA) accumulation in wheat leaves. Further, we sprayed glycerol in a wheat field and found that it significantly (p < 0.05) reduced the severity of powdery mildew disease and lessened disease-associated kernel weight loss, all without causing any noticeable degradation in wheat seed quality. PMID:27708588

  7. Fermentation of glycerol into ethanol in a microbial electrolysis cell driven by a customized consortium.

    PubMed

    Speers, Allison M; Young, Jenna M; Reguera, Gemma

    2014-06-03

    The in situ generation of ethanol from glycerol-containing wastewater shows promise to improve the economics of the biodiesel industry. Consequently, we developed a microbial electrolysis cell (MEC) driven by the synergistic metabolisms of the exoelectrogen Geobacter sulfurreducens and the bacterium Clostridium cellobioparum, which fermented glycerol into ethanol in high yields (90%) and produced fermentative byproducts that served as electron donors for G. sulfurreducens. Syntrophic cooperation stimulated glycerol consumption, ethanol production, and the conversion of fermentation byproducts into cathodic H2 in the MEC. The platform was further improved by adaptively evolving glycerol-tolerant strains with robust growth at glycerol loadings typical of biodiesel wastewater and by increasing the buffering capacity of the anode medium. This resulted in additional increases in glycerol consumption (up to 50 g/L) and ethanol production (up to 10 g/L) at rates that greatly exceeded the capacity of the anode biofilms to concomitantly remove the fermentation byproducts. As a result, 1,3-propanediol was generated as a metabolic sink for electrons not converted into electricity syntrophically. The results highlight the potential of consortia to process glycerol in MECs and provide insights into genetic engineering and system design approaches that can be implemented to further improve MEC performance to satisfy industrial needs.

  8. Production of fumaric acid from biodiesel-derived crude glycerol by Rhizopus arrhizus.

    PubMed

    Zhou, Yuqing; Nie, Kaili; Zhang, Xin; Liu, Shihong; Wang, Meng; Deng, Li; Wang, Fang; Tan, Tianwei

    2014-07-01

    This work investigated the capability of Rhizopus arrhizus to assimilate biodiesel-derived crude glycerol and convert it into fumaric acid. After optimizing the initial glycerol concentration, spore inoculum and yeast extract concentration, smaller pellets (0.7 mm) and higher biomass (3.11 g/L) were obtained when R. arrhizus grew on crude glycerol. It was found that crude glycerol was more suitable than glucose for smaller R. arrhizus pellet forming. When 80 g/L crude glycerol was used as carbon source, the fumaric acid production of 4.37 g/L was obtained at 192 h. With a highest concentration of 22.81 g/L achieved in the co-fermentation of crude glycerol (40 g/L) and glucose (40 g/L) at 144 h, the fumaric acid production was enhanced by 553.6%, compared to the fermentation using glycerol (80 g/L) as sole carbon source. Moreover, the production cost of fumaric acid in co-fermentation was reduced by approximately 14% compared to glucose fermentation.

  9. Trehalose in glycerol-free freezing extender enhances post-thaw survival of boar spermatozoa.

    PubMed

    Athurupana, Rukmali; Takahashi, Daisen; Ioki, Sumire; Funahashi, Hiroaki

    2015-01-01

    Cryopreservation of boar semen is still considered suboptimal due to lower fertility as compared with fresh samples when glycerol, a permeating cryoprotectant, is used. Trehalose is a non-permeable cryoprotectant and nonreducing disaccharide known to stabilize proteins and biologic membranes. The aim of this study was to evaluate the cryosurvival and in vitro penetrability of boar spermatozoa when glycerol was replaced with trehalose in a freezing extender. Ejaculated Berkshire semen samples were diluted in egg yolk-based freezing extender containing glycerol (100 mM) or trehalose (0, 50, 100, 150, 200 and 250 mM) and cryopreserved using a straw freezing procedure. Thawed samples were analyzed for motility, viability, mitochondrial membrane potential (MMP), and acrosome integrity. In experiment 2, penetrability of spermatozoa cryopreserved with 100 mM glycerol or trehalose was examined. Replacement of cryoprotectant glycerol (100 mM) with trehalose had no effect on sperm viability, but replacing it with 100 mM trehalose improved motility, MMP and acrosome integrity significantly. Sperm motility and MMP were considerably higher in 100 mM trehalose, whereas the acrosome integrity was substantially higher in 100-250 mM trehalose. The in vitro penetration rate was also significantly higher in spermatozoa cryopreserved with trehalose (61.3%) than in those cryopreserved with glycerol (43.6%). In conclusion, 100 mM non-permeable trehalose can be used to replace glycerol, a permeating cryoprotectant, for maintenance of better post-thaw quality of boar spermatozoa.

  10. Use of glycerol for producing 1,3-dihydroxyacetone by Gluconobacter oxydans in an airlift bioreactor.

    PubMed

    Hu, Zhong-Ce; Zheng, Yu-Guo; Shen, Yin-Chu

    2011-07-01

    1,3-Dihydroxyacetone can be produced by biotransformation of glycerol with glycerol dehydrogenase from Gluconobacter oxydans cells. Firstly, improvement the activity of glycerol dehydrogenase was carried out by medium optimization. The optimal medium for cell cultivation was composed of 5.6g/l yeast extract, 4.7 g/l glycerol, 42.1g/l mannitol, 0.5 g/l K(2)HPO(4), 0.5 g/l KH(2)PO(4), 0.1g/l MgSO(4)·7H(2)O, and 2.0 g/l CaCO(3) with the initial pH of 4.9. Secondly, an internal loop airlift bioreactor was applied for DHA production from glycerol by resting cells of G. oxydans ZJB09113. Furthermore, the effects of pH, aeration rate and cell content on DHA production and glycerol feeding strategy were investigated. 156.3 ± 7.8 g/l of maximal DHA concentration with 89.8±2.4% of conversion rate of glycerol to DHA was achieved after 72h of biotransformation using 10g/l resting cells at 30°C, pH 5.0 and 1.5vvm of aeration rate.

  11. Effect of water polyamorphism on the molecular vibrations of glycerol in its glassy aqueous solutions.

    PubMed

    Suzuki, Yoshiharu; Mishima, Osamu

    2016-07-14

    A glassy dilute glycerol-water solution undergoes a mutual polyamorphic transition relating to the transition between high- and low-density amorphous ices of solvent water. The polyamorphic transition behavior depends on the glycerol concentration, indicating that the glycerol affects the water polyamorphism. Here, we used the glassy dilute glycerol-water solution of the solute molar fraction of 0.07 and examined the effect of the polyamorphic change in solvent water on the molecular vibrations of glycerol via Raman spectroscopy. It is found that the molecular vibration of glycerol in high-density liquid like solvent water is different from that in the low-density liquid like solvent water and that the change in the molecular vibration of glycerol is synchronized with the polyamorphic transition of solvent water. The dynamical change of the solute molecule relates to the polyamorphic state of solvent water. This result suggests that the polyamorphic fluctuation of water structure emanated from the presumed liquid-liquid critical point plays an important role for the function of aqueous solution under an ambient condition such as the conformational stability of solute, the functional expression of solute, and so on.

  12. Effect of water polyamorphism on the molecular vibrations of glycerol in its glassy aqueous solutions

    NASA Astrophysics Data System (ADS)

    Suzuki, Yoshiharu; Mishima, Osamu

    2016-07-01

    A glassy dilute glycerol-water solution undergoes a mutual polyamorphic transition relating to the transition between high- and low-density amorphous ices of solvent water. The polyamorphic transition behavior depends on the glycerol concentration, indicating that the glycerol affects the water polyamorphism. Here, we used the glassy dilute glycerol-water solution of the solute molar fraction of 0.07 and examined the effect of the polyamorphic change in solvent water on the molecular vibrations of glycerol via Raman spectroscopy. It is found that the molecular vibration of glycerol in high-density liquid like solvent water is different from that in the low-density liquid like solvent water and that the change in the molecular vibration of glycerol is synchronized with the polyamorphic transition of solvent water. The dynamical change of the solute molecule relates to the polyamorphic state of solvent water. This result suggests that the polyamorphic fluctuation of water structure emanated from the presumed liquid-liquid critical point plays an important role for the function of aqueous solution under an ambient condition such as the conformational stability of solute, the functional expression of solute, and so on.

  13. Systematic Engineering of Escherichia coli for d-Lactate Production from Crude Glycerol.

    PubMed

    Wang, Zei Wen; Saini, Mukesh; Lin, Li-Jen; Chiang, Chung-Jen; Chao, Yun-Peng

    2015-11-04

    Crude glycerol resulting from biodiesel production is an abundant and renewable resource. However, the impurities in crude glycerol usually make microbial fermentation problematic. This issue was addressed by systematic engineering of Escherichia coli for the production of d-lactate from crude glycerol. First, mgsA and the synthetic pathways of undesired products were eliminated in E. coli, rendering the strain capable of homofermentative production of optically pure d-lactate. To direct carbon flux toward d-lactate, the resulting strain was endowed with an enhanced expression of glpD-glpK in the glycerol catabolism and of a heterologous gene encoding d-lactate dehydrogenase. Moreover, the strain was evolved to improve its utilization of cruder glycerol and subsequently equipped with the FocA channel to export intracellular d-lactate. Finally, the fed-batch fermentation with two-phase culturing was carried out with a bioreactor. As a result, the engineered strain enabled production of 105 g/L d-lactate (99.9% optical purity) from 121 g/L crude glycerol at 40 h. The result indicates the feasibility of our approach to engineering E. coli for the crude glycerol-based fermentation.

  14. Application of Glycerol for Induced Powdery Mildew Resistance in Triticum aestivum L.

    PubMed

    Li, Yinghui; Song, Na; Zhao, Chuanzhi; Li, Feng; Geng, Miaomiao; Wang, Yuhui; Liu, Wanhui; Xie, Chaojie; Sun, Qixin

    2016-01-01

    Previous work has demonstrated that glycerol-3-phosphate (G3P) and oleic acid (18:1) are two important signal molecules associated with plant resistance to fungi. In this article, we provide evidence that a 3% glycerol spray application 1-2 days before powdery mildew infection and subsequent applications once every 4 days was sufficient to stimulate the plant defense responses without causing any significant damage to wheat leaves. We found that G3P and oleic acid levels were markedly induced by powdery mildew infection. In addition, TaGLI1 (encoding a glycerol kinase) and TaSSI2 (encoding a stearoylacyl carrier protein fatty acid desaturase), two genes associated with the glycerol and fatty acid (FA) pathways, respectively, were induced by powdery mildew infection, and their promoter regions contain some fungal response elements. Moreover, exogenous application of glycerol increased the G3P level and decreased the level of oleic acid (18:1). Glycerol application induced the expression of pathogenesis-related (PR) genes (TaPR-1, TaPR-2, TaPR-3, TaPR-4, and TaPR-5), induced the generation of reactive oxygen species (ROS) before powdery mildew infection, and induced salicylic acid (SA) accumulation in wheat leaves. Further, we sprayed glycerol in a wheat field and found that it significantly (p < 0.05) reduced the severity of powdery mildew disease and lessened disease-associated kernel weight loss, all without causing any noticeable degradation in wheat seed quality.

  15. Dynamic Mechanisms of the Bactericidal Action of an Al2O3-TiO2-Ag Granular Material on an Escherichia coli Strain

    PubMed Central

    Tartanson, Marie-Anne; Rivallin, Matthieu; Pecastaings, Sophie; Chis, Cristian V.; Penaranda, Diego; Roques, Christine; Faur, Catherine

    2015-01-01

    The bactericidal activity of an Al2O3-TiO2-Ag granular material against an Escherichia coli strain was confirmed by a culture-based method. In particular, 100% of microorganisms were permanently inactivated in 30 to 45 min. The present work aimed to investigate the mechanisms of the bactericidal action of this material and their dynamics on Escherichia coli using different techniques. Observations by transmission electron microscopy (TEM) at different times of disinfection revealed morphological changes in the bacteria as soon as they were put in contact with the material. Notably highlighted were cell membrane damage; cytoplasm detachment; formation of vacuoles, possibly due to DNA condensation, in association with regions exhibiting different levels of electron density; and membrane lysis. PCR and flow cytometry analyses were used to confirm and quantify the observations of cell integrity. The direct exposure of cells to silver, combined with the oxidative stress induced by the reactive oxygen species (ROS) generated, was identified to be responsible for these morphological alterations. From the first 5 min of treatment with the Al2O3-TiO2-Ag material, 98% of E. coli isolates were lysed. From 30 min, cell viability decreased to reach total inactivation, although approximately 1% of permeable E. coli cells and 1% of intact cells (105 genomic units · ml−1) were evidenced. This study demonstrates that the bactericidal effect of the material results from a synergic action of desorbed and supported silver. Supported silver was shown to generate the ROS evidenced. PMID:26253665

  16. In-situ detection of local avalanche breakdown and large magnetoresistance in Ag/SiO2/p-Si:B/SiO2/Ag device

    NASA Astrophysics Data System (ADS)

    He, Xiong; Sun, Zhigang; Pang, Yuyu; Li, Yuechou

    2017-03-01

    Local avalanche breakdown in an Ag/SiO2/p-Si:B/SiO2/Ag device was successfully detected by an in-situ detection circuit, which was composed of a p-Si:B substrate, two p-Si:B/SiO2/Ag metal-oxide-semiconductor (MOS) structures formed on it, and a voltmeter. In our device, we observed a series of discharge peaks in the voltage-current curves which were corresponding to the generation of local plasmas in avalanche regimes. The generation of local plasmas led to a sudden increase in carriers concentration in the substrate which resulted in sudden voltage drops across the detection circuit, and then the MOS structures started to discharge which led to discharge peaks observed in V-I characteristics. More interesting, we found that the shape and amplitude of discharge peaks strongly depended on the setting of current steps of current source, owing to the discharging progresses. The avalanche breakdown based magnetoresistance (MR) effects were also studied. The value of MR in avalanche breakdown regime was about 40% which was two orders of magnitude higher than the MR value in other regimes. This work provides a simple and convenient method to explore the local avalanche breakdown effect and pave a way to acquire the MR effects based on avalanche breakdown.

  17. Conductive and transparent multilayer films for low-temperature TiO2/Ag/SiO2 electrodes by E-beam evaporation with IAD.

    PubMed

    Chiu, Po-Kai; Lee, Chao-Te; Chiang, Donyau; Cho, Wen-Hao; Hsiao, Chien-Nan; Chen, Yi-Yan; Huang, Bo-Ming; Yang, Jer-Ren

    2014-01-16

    Conductive and transparent multilayer thin films consisting of three alternating layers (TiO2/Ag/SiO2, TAS) have been fabricated for applications as transparent conducting oxides. Metal oxide and metal layers were prepared by electron-beam evaporation with ion-assisted deposition, and the optical and electrical properties of the resulting films as well as their energy bounding characteristics and microstructures were carefully investigated. The optical properties of the obtained TAS material were compared with those of well-known transparent metal oxide glasses such as ZnO/Ag/ZnO, TiO2/Ag/TiO2, ZnO/Cu/ZnO, and ZnO/Al/ZnO. The weathering resistance of the TAS film was improved by using a protective SiO2 film as the uppermost layer. The transmittance spectra and sheet resistance of the material were carefully measured and analyzed as a function of the layer thickness. By properly adjusting the thickness of the metal and dielectric films, a low sheet resistance of 6.5 ohm/sq and a high average transmittance of over 89% in the 400 to 700 nm wavelength regions were achieved. We found that the Ag layer played a significant role in determining the optical and electrical properties of this film.

  18. Correlation between the optical performance of TiO2-Ag-TiO2 multilayers and the interface roughness between the layers

    NASA Astrophysics Data System (ADS)

    von Blanckenhagen, Bernhard; Tonova, Diana

    2005-09-01

    Ag-dielectric multilayers are widely used in the production of heat reflecting filters, induced transmission filters, beam splitters, etc. The performance of such coatings in the visible part of the spectrum is sometimes strongly influenced by a plasmon absorption in the Ag-layer or a surface plasmon absorption in the Ag-dielectric interfaces. The strength of the plasmon absorption is very sensitive to the layer structure, the light polarization and the angle of incidence. As a result, the target specifications for reflection and transmission are not reached easily. We investigate PVD-deposited TiO2-Ag-TiO2 multilayers by means of optical reflection and transmission and Grazing Incidence X-ray Reflectometry (GIXR). The GIXR-method yields the individual layers thicknesses and the interface roughness. Some of the coatings have a broad absorption peak between 500 and 400nm that cannot be modeled using the bulk dielectric function of Ag. The magnitude of the absorption peak is correlated with the measured roughness of the TiO2-Ag interfaces. The analysis of the results shows the critical parameters for the deposition process.

  19. Magnetically separable Fe3O4@SiO2@TiO2-Ag microspheres with well-designed nanostructure and enhanced photocatalytic activity.

    PubMed

    Chi, Yue; Yuan, Qing; Li, Yanjuan; Zhao, Liang; Li, Nan; Li, Xiaotian; Yan, Wenfu

    2013-11-15

    Major efforts in modern material chemistry are devoted to the design and fabrication of nanostructured systems with tunable physical-chemical properties for advanced catalytic applications. Here, a novel Fe3O4@SiO2@TiO2-Ag nanocomposite has been synthesized and characterized by a series of techniques including SEM, TEM, XRD, XPS as well as magnetization measurement and subsequently tested for the photocatalytic activities. The well-designed nanocomposite exhibits significantly superior activity to that of the commercial Degussa P25 thanks to the suppression of electron-hole pairs from recombination by Ag nanoparticles, and can be easily recycled by applying an external magnetic field while maintaining the catalytic activity without significant decrease even after running 10 times. The unique nanostructure makes Fe3O4@SiO2@TiO2-Ag a highly efficient, recoverable, stable, and cost-effective photocatalytic system offering broad opportunities in the field of catalyst synthesis and application.

  20. Increasing levels of the endocannabinoid 2-AG is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease

    PubMed Central

    Mounsey, Ross B.; Mustafa, Sarah; Robinson, Lianne; Ross, Ruth A.; Riedel, Gernot; Pertwee, Roger G.; Teismann, Peter

    2015-01-01

    Parkinson's disease (PD) is a common chronic neurodegenerative disorder, usually of idiopathic origin. Symptoms including tremor, bradykinesia, rigidity and postural instability are caused by the progressive loss of dopaminergic neurons in the nigrostriatal region of the brain. Symptomatic therapies are available but no treatment slows or prevents the loss of neurons. Neuroinflammation has been implicated in its pathogenesis. To this end, the present study utilises the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin to reproduce the pattern of cell death evident in PD patients. Herein, the role of a potential regulator of an immune response, the endocannabinoid system (ECS), is investigated. The most prevalent endocannabinoid, 2-arachidonoylglycerol (2-AG) (3 and 5 mg/kg), was added exogenously and its enzymatic degradation inhibited to provide protection against MPTP-induced cell death. Furthermore, the addition of DFU (25 mg/kg), a selective inhibitor of inflammatory mediator cyclooxygenase-2 (COX-2), potentiated these effects. Levels of 2-AG were shown to be upregulated in a time- and region-specific manner following MPTP administration, indicating that the ECS represents a natural defence mechanism against inflammation, potentiation of which could provide therapeutic benefits. The results expand the current understanding of the role that this signalling system has and its potential influence in PD. PMID:26244281

  1. Improved electron transfer and plasmonic effect in dye-sensitized solar cells with bi-functional Nb-doped TiO2/Ag ternary nanostructures.

    PubMed

    Park, Jung Tae; Chi, Won Seok; Jeon, Harim; Kim, Jong Hak

    2014-03-07

    TiO2 nanoparticles are surface-modified via atom transfer radical polymerization (ATRP) with a hydrophilic poly(oxyethylene)methacrylate (POEM), which can coordinate to the Ag precursor, i.e. silver trifluoromethanesulfonate (AgCF3SO3). Following the reduction of Ag ions, a Nb2O5 doping process and calcination at 450 °C, bi-functional Nb-doped TiO2/Ag ternary nanostructures are generated. The resulting nanostructures are characterized by energy-filtering transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy. The dye-sensitized solar cell (DSSC) based on the Nb-doped TiO2/Ag nanostructure photoanode with a polymerized ionic liquid (PIL) as the solid polymer electrolyte shows an overall energy conversion efficiency (η) of 6.9%, which is much higher than those of neat TiO2 (4.7%) and Nb-doped TiO2 (5.4%). The enhancement of η is mostly due to the increase of current density, attributed to the improved electron transfer properties including electron injection, collection, and plasmonic effects without the negative effects of charge recombination or problems with corrosion. These properties are supported by intensity modulated photocurrent/voltage spectroscopy (IMPS/IMVS) and incident photon-to-electron conversion efficiency (IPCE) measurements.

  2. Conductive and transparent multilayer films for low-temperature TiO2/Ag/SiO2 electrodes by E-beam evaporation with IAD

    PubMed Central

    2014-01-01

    Conductive and transparent multilayer thin films consisting of three alternating layers (TiO2/Ag/SiO2, TAS) have been fabricated for applications as transparent conducting oxides. Metal oxide and metal layers were prepared by electron-beam evaporation with ion-assisted deposition, and the optical and electrical properties of the resulting films as well as their energy bounding characteristics and microstructures were carefully investigated. The optical properties of the obtained TAS material were compared with those of well-known transparent metal oxide glasses such as ZnO/Ag/ZnO, TiO2/Ag/TiO2, ZnO/Cu/ZnO, and ZnO/Al/ZnO. The weathering resistance of the TAS film was improved by using a protective SiO2 film as the uppermost layer. The transmittance spectra and sheet resistance of the material were carefully measured and analyzed as a function of the layer thickness. By properly adjusting the thickness of the metal and dielectric films, a low sheet resistance of 6.5 ohm/sq and a high average transmittance of over 89% in the 400 to 700 nm wavelength regions were achieved. We found that the Ag layer played a significant role in determining the optical and electrical properties of this film. PMID:24433437

  3. Chemical assembly of TiO2 and TiO2@Ag nanoparticles on silk fiber to produce multifunctional fabrics.

    PubMed

    Li, Guohong; Liu, Hong; Zhao, Hongshi; Gao, Yuqiang; Wang, Jiyang; Jiang, Huaidong; Boughton, R I

    2011-06-01

    A carefully designed surface modification technique for the manufacture of multifunctional silk textile nanocomposite materials is successfully developed by the functionalization of silk with TiO(2) and TiO(2)@Ag nanoparticles (NPs). The NPs are assembled onto a silk substrate through covalent linkages, including enediol ligand-metal oxide bonding, resin dehydration and the acylation of silk. Owing to the strong chemical bonding, silk fibroin fabric (SFF) and the NPs form a stable composite system. The functionalized SFF, especially TiO(2)@Ag NP-functionalized SFF are endowed with remarkable UV protection properties, and an efficient anti-bacterial capability toward Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Furthermore, the nearly total photodegradation of methylene orange (MO) under UV illumination illustrates that functionalized SFF possesses high photocatalytic and self-cleaning capability. This multifunctional silk material satisfies the market demand for natural "smart" products, and is a promising practical material for use in the textile industry, hospital sterilization and environmental cleanup.

  4. Hierarchical Fe3O4@MoS2/Ag3PO4 magnetic nanocomposites: Enhanced and stable photocatalytic performance for water purification under visible light irradiation

    NASA Astrophysics Data System (ADS)

    Guo, Na; Li, Haiyan; Xu, Xingjian; Yu, Hongwen

    2016-12-01

    Novel hierarchical Fe3O4@MoS2/Ag3PO4 magnetic nanophotocatalyst with remarkable photocatalytic capability were prepared by simply depositing the Ag3PO4 onto the surface of crumpled Fe3O4@MoS2 nanosphere. The nanocomposites were characterized by XRD, TEM, HRTEM, XPS, BET, and UV-vis DRS. The outcome of the photocatalytic experiments demonstrated that Fe3O4@MoS2/Ag3PO4 with 6 wt% content of Ag3PO4 (FM/A-6%) showed the highest photocatalytic activity upon the degradation Congo red (CR) and Rhodamine B (RhB) under both visible light and simulated sunlight irradiation. In addition, FM/A-6% possessed larger specific surface area (76.56 m2/g) and excellent optical property. The possible Z-scheme charge carriers transfer mechanism for the enhanced photocatalytic properties of the FM/A-6% was also discussed. The Z-scheme charge carriers transfer mechanism established between MoS2 and Ag3PO4 facilitate the charge separation efficiency. Moreover, FM/A-6% can be separated and collected easily by external magnetic field and maintain high activity after five times photoreaction cycles. Given the remarkable photocatalytic performance and high stability of FM/A-6% nanocomposite, it is looking forward to exhibit great potential for applications in water purification.

  5. Synthesis and magnetic structure of the layered manganese oxide selenide Sr2MnO2Ag1.5Se2

    NASA Astrophysics Data System (ADS)

    Blandy, Jack N.; Boskovic, Jelena C.; Clarke, Simon J.

    2017-01-01

    The synthesis of a high-purity sample of the layered oxide selenide Sr2MnO2Ag1.5Se2 is reported. At ambient temperature it crystallises in the space group I4/mmm with two formula units in the unit cell and lattice parameters a=4.08771(1) Å, c=19.13087(8) Å. The compound displays mixed-valent manganese in a formal oxidation state close to +2.5 and powder neutron diffraction measurements reveal that below the Néel temperature of 63(1) K this results in an antiferromagnetic structure which may be described as A-type, modelled in the magnetic space group PI4/mnc (128.410 in the Belov, Neronova and Smirnova (BNS) scheme) in which localised Mn moments of 3.99(2) μB are arranged in ferromagnetic layers which are coupled antiferromagnetically. In contrast to the isostructural compound Sr2MnO2Cu1.5S2, Sr2MnO2Ag1.5Se2 does not display long range ordering of coinage metal ions and vacancies, nor may significant amounts of the coinage metal readily be deintercalated using soft chemical methods.

  6. Synthesis of core-shell nanostructured magnetic photocatalyst Fe3O4@SiO2@Ag3PO4 with excellent visible-light-responding photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Yao, Yang Rong; Huang, Wan Zhen; Zhou, Huan; Cui, Xia; Zheng, Yi Fan; Song, Xu Chun

    2014-11-01

    A core-shell nanostructured magnetic photocatalyst Fe3O4@SiO2@Ag3PO4 with a grain size ranging from 200 to 400 nm was prepared via a facile and effective method. The as-prepared products were characterized using X-ray diffraction, high-angle annular dark field-scanning transmission electron microscopy, energy-dispersive spectroscopy, and UV-Vis diffuse reflectance spectra. The photocatalytic activity was evaluated by the degradation of 10-5 M RhB solution under visible light irradiation with a cut-off filter ( λ ≥ 420 nm). The results showed that nearly 100 % color removal efficiency was achieved in 45 min with the presence of Fe3O4@SiO2@Ag3PO4 photocatalyst. Furthermore, it can be easily recollected from the solution by magnetic separation and efficiently recycled without major loss of activity due to its superior magnetic responsibility and extremely high reusability, exhibiting highly potential applications in water purification avoiding the secondary pollution.

  7. Glycerolipid biosynthesis in Saccharomyces cerevisiae: sn-glycerol-3-phosphate and dihydroxyacetone phosphate acyltransferase activities.

    PubMed Central

    Schlossman, D M; Bell, R M

    1978-01-01

    Yeast acyl-coenzyme A:dihydroxyacetone-phosphate O-acyltransferase (DHAP acyltransferase; EC 2.3.1.42) was investigated to (i) determine whether its activity and that of acyl-coenzyme A:sn-glycerol-3-phosphate O-acyltransferase (glycerol-P acyltransferase; EC 2.3.1.15) represent dual catalytic functions of a single membranous enzyme, (ii) estimate the relative contributions of the glycerol-P and DHAP pathways for yeast glycerolipid synthesis, and (iii) evaluate the suitability of yeast for future genetic investigations of the eucaryotic glycerol-P and DHAP acyltransferase activities. The membranous DHAP acyltransferase activity showed an apparent Km of 0.79 mM for DHAP, with a Vmax of 5.3 nmol/min per mg, whereas the glycerol-P acyltransferase activity showed an apparent Km of 0.05 mM for glycerol-P, with a Vmax of 3.4 nmol/min per mg. Glycerol-P was a competitive inhibitor (Ki, 0.07 mM) of the DHAP acyltransferase activity, and DHAP was a competitive inhibitor (Ki, 0.91 mM) of the glycerol-P acyltransferase activity. The two acyltransferase activities exhibited marked similarities in their pH dependence, acyl-coenzyme A chain length preference and substrate concentration dependencies, thermolability, and patterns of inactivation by N-ethylmaleimide, trypsin, and detergents. Thus, the data strongly suggest that yeast glycerol-P and DHAP acyltransferase activities represent dual catalytic functions of a single membrane-bound enzyme. Furthermore, since no acyl-DHAP oxidoreductase activity could be detected in yeast membranes, the DHAP pathway for glycerolipid synthesis may not operate in yeast. PMID:25265

  8. Energy recovery from waste glycerol by utilizing thermal water vapor plasma.

    PubMed

    Tamošiūnas, Andrius; Valatkevičius, Pranas; Gimžauskaitė, Dovilė; Jeguirim, Mejdi; Mėčius, Vladas; Aikas, Mindaugas

    2017-04-01

    Glycerol, considered as a waste feedstock resulting from biodiesel production, has received much attention in recent years due to its properties, which offer to recover energy. The aim of this study was to investigate the use of a thermal water vapor plasma for waste (crude) glycerol conversion to synthesis gas, or syngas (H2 + CO). In parallel of crude glycerol, a pure glycerol (99.5%) was used as a reference material in order to compare the concentrations of the formed product gas. A direct current (DC) arc plasma torch stabilized by a mixture of argon/water vapor was utilized for the effective glycerol conversion to hydrogen-rich synthesis gas. It was found that after waste glycerol treatment, the main reaction products were gases with corresponding concentrations of H2 50.7%, CO 23.53%, CO2 11.45%, and CH4 3.82%, and traces of C2H2 and C2H6, which concentrations were below 0.5%. The comparable concentrations of the formed gas products were obtained after pure glycerol conversion-H2 46.4%, CO 26.25%, CO2 11.3%, and CH4 4.7%. The use of thermal water vapor plasma producing synthesis gas is an effective method to recover energy from both crude and pure glycerol. The performance of the glycerol conversion system was defined in terms of the produced gas yield, the carbon conversion efficiency, the cold gas efficiency, and the specific energy requirements.

  9. Uncoupling effect of polyunsaturated fatty acid deficiency in isolated rat hepatocytes:effect on glycerol metabolism.

    PubMed Central

    Piquet, M A; Fontaine, E; Sibille, B; Filippi, C; Keriel, C; Leverve, X M

    1996-01-01

    The effects of a 4-week deficiency in polyunsaturated fatty acids (PUFA) in isolated rat hepatocytes have been investigated for oxidative phosphorylation and fatty acid, dihydroxyacetone (DHA) or glycerol metabolism. Oxygen uptake was significantly increased (by 20%) with or without fatty acid addition (octanoate or oleate) in the PUFA-deficient group compared with controls. The effect persisted after oligomycin addition but not after that of potassium cyanide, leading to the conclusion that, in these intact cells, the mitochondria were uncoupled. The PUFA-deficient group exhibited a significant decrease in the cytosolic ATP/ADP ratio, whereas the mitochondrial ratio was not affected. PUFA deficiency led to a 16% decrease in DHA metabolism owing to a 34% decrease in glycerol kinase activity; the significant decrease in the ATP/ADP ratio was accompanied by an increase in the fractional glycolytic flux. In contrast, glycerol metabolism was significantly enhanced in the PUFA-deficient group. The role of the glycerol 3-phosphate dehydrogenase step in this stimulation was evidenced in hepatocytes perifused with glycerol and octanoate in the presence of increased concentrations of 2,4-dinitrophenol (Dnp): uncoupling with Dnp led to an enhancement of glycerol metabolism, as found in PUFA deficiency, although it was more pronounced than in controls. The matrix/cytosol gradients for redox potential and ATP/ADP ratio were lower in cells from PUFA-deficient rats, suggesting a decreased mitochondrial membrane potential in accordance with the uncoupling effect. Moreover, a doubling of the mitochondrial glycerol 3-phosphate dehydrogenase activity in the PUFA-deficient group compared with controls led us to conclude that the activation of glycerol metabolism is the consequence of two mitochondrial effects: uncoupling and an increase in glycerol 3-phosphate dehydrogenase activity. PMID:8760348

  10. Development of bioelectrocatalytic activity stimulates mixed-culture reduction of glycerol in a bioelectrochemical system

    PubMed Central

    Zhou, Mi; Freguia, Stefano; Dennis, Paul G; Keller, Jürg; Rabaey, Korneel

    2015-01-01

    In a microbial bioelectrochemical system (BES), organic substrate such as glycerol can be reductively converted to 1,3-propanediol (1,3-PDO) by a mixed population biofilm growing on the cathode. Here, we show that 1,3-PDO yields positively correlated to the electrons supplied, increasing from 0.27 ± 0.13 to 0.57 ± 0.09 mol PDO mol−1 glycerol when the cathodic current switched from 1 A m−2 to 10 A m−2. Electrochemical measurements with linear sweep voltammetry (LSV) demonstrated that the biofilm was bioelectrocatalytically active and that the cathodic current was greatly enhanced only in the presence of both biofilm and glycerol, with an onset potential of −0.46 V. This indicates that glycerol or its degradation products effectively served as cathodic electron acceptor. During long-term operation (> 150 days), however, the yield decreased gradually to 0.13 ± 0.02 mol PDO mol−1 glycerol, and the current–product correlation disappeared. The onset potentials for cathodic current decreased to −0.58 V in the LSV tests at this stage, irrespective of the presence or absence of glycerol, with electrons from the cathode almost exclusively used for hydrogen evolution (accounted for 99.9% and 89.5% of the electrons transferred at glycerol and glycerol-free conditions respectively). Community analysis evidenced a decreasing relative abundance of Citrobacter in the biofilm, indicating a community succession leading to cathode independent processes relative to the glycerol. It is thus shown here that in processes where substrate conversion can occur independently of the electrode, electroactive microorganisms can be outcompeted and effectively disconnected from the substrate. PMID:25817314

  11. Anaerobic codigestion of sewage sludge and glycerol, focusing on process kinetics, microbial dynamics and sludge dewaterability.

    PubMed

    Jensen, P D; Astals, S; Lu, Y; Devadas, M; Batstone, D J

    2014-12-15

    Anaerobic codigestion (AcoD) is a proven option to significantly boost biogas production while utilizing existing digesters and infrastructure. The aim of the present research was to conduct an exhaustive study regarding anaerobic codigestion of mixed sewage sludge and crude glycerol considering impacts on organic load, hydraulic load, process performance and microbial community. The methane potential of crude glycerol varied from 370 mL CH4·g(-1) VS to 483 mL CH4·g(-1) VS for different samples tested. The half maximal inhibitory concentration of crude glycerol was 1.01 g VS L(-1), and the primary mechanism of inhibition was through overload from rapid fermentation rather than the presence of toxic compounds in the crude glycerol. In continuous operation over 200 days, feeding glycerol at up to 2% v/v, increased organic load by up to 70% and resulted in a 50% increase in methane production. Glycerol dosing resulted in no change in apparent dewaterability, with both codigestion and control reactors returning values of 22%-24%. Members of the phylum Thermotogae emerged as a niche population during AcoD of sewage sludge and glycerol; however there was no gross change in microbial community structure and only minimal changes in diversity. AcoD did not result in synergisms between sewage sludge and crude glycerol. Actually, at dose rate up to 2% v/v glycerol dosing is still an effective strategy to increase the organic loading rate of continuous anaerobic digesters with minimal impact of the hydraulic retention time. Nonetheless, the dose rate must be managed to: (i) prevent process inhibition and (ii) ensure sufficient degradation time to produce a stable biosolids product.

  12. Evidence of moisture control on the methylation of branched glycerol dialkyl glycerol tetraethers in semi-arid and arid soils

    NASA Astrophysics Data System (ADS)

    Dang, Xinyue; Yang, Huan; Naafs, B. David A.; Pancost, Richard D.; Xie, Shucheng

    2016-09-01

    The distribution of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) is influenced by growth temperature and pH. This results in the widespread application of the brGDGT-based MBT(‧)/CBT proxy (MBT - methylation of branched tetraethers, CBT - cyclization of branched tetraethers) in terrestrial paleo-environmental reconstructions. Recently, it was shown that the amount of precipitation could also have an impact on CBT, as well as the abundance of brGDGTs relative to that of archaeal isoprenoidal (iso)GDGTs (Ri/b) and the absolute abundance of brGDGTs, potentially complicating the use of MBT/CBT as paleothermometer. However, the full influence of hydrology, and in particular soil water content (SWC), on GDGT distributions remains unclear. Here we investigated variations in the GDGT distribution across a SWC gradient (0-61%) around Qinghai Lake in the Tibetan Plateau, an arid to semiarid region in China. Our results demonstrate that SWC affects the brGDGT distribution. In particular, we show that SWC has a clear impact on the degree of methylation of C6-methylated brGDGTs, whereas C5-methylated brGDGTs are more impacted by temperature. This results in a combined SWC and temperature control on MBT‧. In this context we propose a diagnostic parameter, the IR6ME (relative abundance of C6-methylated GDGTs) index, to evaluate the applicability of brGDGT-based paleotemperature reconstructions. Using the global dataset, expanded with our own data, MBT‧ has a significant correlation with mean annual air temperature when IR6ME < 0.5, allowing for the use of MBT‧/CBT as temperature proxy. However, MBT‧ has a significant correlation with mean annual precipitation (i.e., a substantial reflection of SWC impact) when IR6ME > 0.5, implying that MBT‧ may respond to hydrological change in these regions and can be used as a proxy for MAP.

  13. Concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers in sinking particles south of Java

    NASA Astrophysics Data System (ADS)

    Chen, Wenwen; Mohtadi, Mahyar; Schefuß, Enno; Mollenhauer, Gesine

    2016-06-01

    In this study, we obtained concentrations and abundance ratios of long-chain alkenones and glycerol dialkyl glycerol tetraethers (GDGTs) in a one-year time-series of sinking particles collected with a sediment trap moored from December 2001 to November 2002 at 2200 m water depth south of Java in the eastern Indian Ocean. We investigate the seasonality of alkenone and GDGT fluxes as well as the potential habitat depth of the Thaumarchaeota producing the GDGTs entrained in sinking particles. The alkenone flux shows a pronounced seasonality and ranges from 1 μg m-2 d-1 to 35 μg m-2 d-1. The highest alkenone flux is observed in late September during the Southeast monsoon, coincident with high total organic carbon fluxes as well as high net primary productivity. Flux-weighted mean temperature for the high flux period using the alkenone-based sea-surface temperature (SST) index U37K‧ is 26.7 °C, which is similar to satellite-derived Southeast (SE) monsoon SST (26.4 °C). The GDGT flux displays a weaker seasonality than that of the alkenones. It is elevated during the SE monsoon period compared to the Northwest (NW) monsoon and intermonsoon periods (approximately 2.5 times), which is probably related to seasonal variation of the abundance of Thaumarchaeota, or to enhanced export of GDGTs by aggregation with sinking phytoplankton detritus. Flux-weighted mean temperature inferred from the GDGT-based TEX86H index is 26.2 °C, which is 1.8 °C lower than mean annual (ma) SST but similar to SE monsoon SST. As the time series of TEX86H temperature estimates, however, does not record a strong seasonal amplitude, we infer that TEX86H reflects ma upper thermocline temperature at approximately 50 m water depth.

  14. Distribution of Glycerol Dialkyl Glycerol Tetraethers in Soils from Two Environmental Transects in the U.S

    NASA Astrophysics Data System (ADS)

    Dirghangi, S. S.; Pagani, M.; Hren, M. T.; Tipple, B. J.

    2012-12-01

    Glycerol Dialkyl Glycerol Tetraethers (GDGT) of both archaeal and bacterial origins form the basis of new temperature proxies applicable to soils, lake and marine sediments. In soils, branched GDGTs are prevalent and the abundance of methyl or cyclic groups in these compounds has been calibrated to mean-annual temperatures using MBT and CBT indices. However, soil pH is also known to be an important variable controlling the distribution of branched GDGTs. The factors influencing soil pH include bedrock type, vegetation, soil microbial activity, precipitation amount, drainage etc. For this study, we evaluate the distribution of branched GDGTs from two soil transects in the United States: a dry, western transect that covers four western states, and a wet, east-coast transect from Maine to Georgia in order to assess the effect of precipitation on the distribution of soil GDGTs. Our results show distinctly different GDGT distributions across climatic regions, with dry western soils predominantly characterized by crenarchaeal isoprenoidal GDGTs and moist-temperate east-coast transect soils expressing mostly branched GDGTs. Predominance of isoprenoidal GDGTs in the western soils is related to the degree of aeration which in turn is related to precipitation amount. We also observe a substantial increase in the offset between measured mean-annual temperatures (MAT) and MBT/CBT-based MAT below an annual precipitation of 700-800mm per year. These data suggest that while soil tetraethers work well as a temperature proxy in moist-temperate regimes, they do not produce reliable measurements of temperature in sediments sourced from areas with less than 700-800mm per year precipitation.

  15. EFFECT OF TEMPERATURE AND GLYCEROL ON THE HYDROGEN-BOND DYNAMICS OF WATER

    SciTech Connect

    Ghattyvenkatakrishna, Pavan K; Uberbacher, Edward C

    2013-01-01

    The effect of glycerol, water and glycerol-water binary mixtures on the structure and dynamics of biomolecules has been well studied. However, the effect of varying glycerol concentration and temperature on the dynamics of water has not received due attention. We have studied the effect of concentration and temperature on the hydrogen bonded network formed by water molecules. A strong correlation between the relaxation time of the network and average number of hydrogen bonds per water molecules was found. The radial distribution function of water oxygens and hydrogens clarifies the effect of concentration on the structure and clustering of water.

  16. Shear propagation in the terahertz dynamics of water-glycerol mixtures

    SciTech Connect

    Cunsolo, Alessandro; Kodituwakku, Chaminda N.; Bencivenga, Filippo; Said, Ayman H.

    2013-11-14

    Inelastic X-ray and neutron scattering techniques were jointly used to investigate the dynamics of water-glycerol mixtures at different concentrations and temperatures. It was observed that even relatively low concentrations of glycerol increase the damping of shear modes, as a consequence of the known ability of glycerol to disrupt the hydrogen bond network of water. A similar trend was observed when increasing the temperature, which suggests the presence of a locus in the concentration-temperature plane marking a crossover in the shear modulus.

  17. Enhanced production of dihydroxyacetone from glycerol by overexpression of glycerol dehydrogenase in an alcohol dehydrogenase-deficient mutant of Gluconobacter oxydans.

    PubMed

    Li, Ming-hua; Wu, Jian; Liu, Xu; Lin, Jin-ping; Wei, Dong-zhi; Chen, Hao

    2010-11-01

    Gluconobacter oxydans can rapidly and incompletely oxidize glycerol to dihydroxyacetone (DHA), a versatile product extensively used in cosmetic, chemical and pharmaceutical industries. To improve DHA production, the glycerol dehydrogenase (GDH) responsible for DHA formation was overexpressed in G. oxydans M5AM, in which the gene coding for the membrane-bound alcohol dehydrogenase (ADH) was interrupted. Real-time PCR and enzyme activity assay revealed that the absence of ADH together with the overexpression of GDH gene resulted in an increased GDH activity in the resulting strain M5AM/GDH, which led to a substantially enhanced production of DHA in a resting cell system. In a batch biotransformation process, M5AM/GDH exhibited a 2.4-fold increased DHA productivity of 2.4g/g CDW/h from 1.0g/g CDW/h, yielding 96g/L DHA from 100g/L glycerol. When 140g/L glycerol was supplied, a final DHA concentration of 134g/L was accumulated within 14h. In four repeated batch runs, 385g DHA over a time period of 34h was achieved from 400g glycerol with an average productivity of 2.2g/g CDW/h. These results indicated that this newly developed strain G. oxydans M5AM/GDH with high productivity and increased tolerance against product inhibition has potential for DHA production in an industrial bioconversion process.

  18. (NH4)2SO4 heterogeneous nucleation and glycerol evaporation of (NH4)2SO4-glycerol system in its dynamic efflorescence process

    NASA Astrophysics Data System (ADS)

    Cai, Chen; Luan, Ye-mei; Shi, Xiao-min; Zhang, Yun-hong

    2017-02-01

    Using the FTIR-ATR technique, we investigated the heterogeneous nucleation process of aqueous (NH4)2SO4 binary droplets and (NH4)2SO4/glycerol ternary droplets. From the red shift of δ-NH4+ with a linearly declining relative humidity (RH), the ERHs of pure (NH4)2SO4 droplets and mixed (NH4)2SO4/glycerol droplets with different organic-inorganic ratio (OIR) of 1:4, 1:2 and 1:1 ranges from ∼51.9 to ∼34.9%, ∼49.8 to ∼33.0%, ∼48.0 to ∼30.6% and ∼43.7 to ∼25.2%, respectively. From the changing absorbance of δ-NH4+ band, we determined the heterogeneous nucleation rates of crystalline (NH4)2SO4 in the pure and mixed droplets. The interfacial tension between an (NH4)2SO4 critical nucleus and surrounding (NH4)2SO4 solution was determined using classical nucleation theory and experimental data to be 0.031 ± 0.002 J m-2. Evaporation of glycerol in (NH4)2SO4/glycerol ternary droplets are also studied to be restrained by participation of (NH4)2SO4. Determined vapour pressure of glycerol is on the same magnitude with results from previous studies.

  19. Crude glycerol as feedstock for the sustainable production of p-hydroxybenzoate by Pseudomonas putida S12.

    PubMed

    Verhoef, Suzanne; Gao, Nisi; Ruijssenaars, Harald J; de Winde, Johannes H

    2014-01-25

    Crude glycerol is a promising renewable feedstock in bioconversion processes for the production of fuels and chemicals. Impurities present in crude glycerol can however, negatively impact the fermentation process. Successful crude glycerol utilization requires robust microbial production hosts that tolerate and preferably, can utilize such impurities. We investigated utilization of crude, unpurified glycerol as a substrate for the production of aromatic compounds by solvent tolerant Pseudomonas putida S12. In high-cell density fed-batch fermentations, P. putida S12 surprisingly performed better on crude glycerol than on purified glycerol. By contrast, growth of Escherichia coli was severely compromised under these high cell density cultivation conditions on crude glycerol. For P. putida S12 the biomass-to-substrate yield, maximum biomass production rate and substrate uptake rate were consistently higher on crude glycerol. Moreover, production of p-hydroxybenzoate by engineered P. putida S12palB5 on crude glycerol showed a 10% yield improvement over production on purified glycerol. P. putida S12 is a favorable host for bioconversion processes utilizing crude glycerol as a substrate. Its intrinsic stress-tolerance properties provide the robustness required for efficient growth and metabolism on this renewable substrate.

  20. Batch stage study of lipid production from crude glycerol derived from yellow grease or animal fats through microalgal fermentation.

    PubMed

    Liang, Yanna; Sarkany, Nicolas; Cui, Yi; Blackburn, James W

    2010-09-01

    A marine microalga, Schizochytrium limacinum SR21 has been found to grow fast on crude glycerol - a major by-product from the current biodiesel industry. Using crude glycerol derived from restaurant used oils (yellow grease), we have determined that glycerol concentrations of 25 and 35 g/l were the optimal ones for untreated and treated crude glycerol in batch cultures, respectively. Biomass dry weight as 8.3 and 13.3g/l were attained for these two doses, respectively. Higher concentrations of glycerol resulted in decreased cell growth due to substrate inhibition and methanol presence. With 35 g/l, the cellular lipid content was the highest - 73.3% among all the doses tested. Animal fats derived crude glycerol also supported algal growth and lipid production. Results from this study set a solid foundation for our ongoing fed-batch process to achieve maximal crude glycerol utilization and lipid production.

  1. Fermentative utilization of glycerol by Escherichia coli and its implications for the production of fuels and chemicals.

    PubMed

    Murarka, Abhishek; Dharmadi, Yandi; Yazdani, Syed Shams; Gonzalez, Ramon

    2008-02-01

    Availability, low prices, and a high degree of reduction make glycerol an ideal feedstock to produce reduced chemicals and fuels via anaerobic fermentation. Although glycerol metabolism in Escherichia coli had been thought to be restricted to respiratory conditions, we report here the utilization of this carbon source in the absence of electron acceptors. Cells grew fermentatively on glycerol and exhibited exponential growth at a maximum specific growth rate of 0.040 +/- 0.003 h(-1). The fermentative nature of glycerol metabolism was demonstrated through studies in which cell growth and glycerol utilization were observed despite blocking several respiratory processes. The incorporation of glycerol in cellular biomass was also investigated via nuclear magnetic resonance analysis of cultures in which either 50% U-13C-labeled or 100% unlabeled glycerol was used. These studies demonstrated that about 20% of the carbon incorporated into the protein fraction of biomass originated from glycerol. The use of U-13C-labeled glycerol also allowed the unambiguous identification of ethanol and succinic, acetic, and formic acids as the products of glycerol fermentation. The synthesis of ethanol was identified as a metabolic determinant of glycerol fermentation; this pathway fulfills energy requirements by generating, in a redox-balanced manner, 1 mol of ATP per mol of glycerol converted to ethanol. A fermentation balance analysis revealed an excellent closure of both carbon (approximately 95%) and redox (approximately 96%) balances. On the other hand, cultivation conditions that prevent H2 accumulation were shown to be an environmental determinant of glycerol fermentation. The negative effect of H2 is related to its metabolic recycling, which in turn generates an unfavorable internal redox state. The implications of our findings for the production of reduced chemicals and fuels were illustrated by coproducing ethanol plus formic acid and ethanol plus hydrogen from glycerol at

  2. Effect of glycerol on retention time and electrical properties of polymer bistable memory devices based on glycerol-modified PEDOT:PSS.

    PubMed

    Park, Boongik; Lee, Junhwan; Kim, Ohyun

    2012-01-01

    The addition of glycerol to Poly(3,4-ethylenedioxythiophene):Poly(styrene sulfonate) (PEDOT:PSS) films affected the bipolar switching characteristics of nonvolatile polymer memory devices (PMDs). Increasing the glycerol/PEDOT:PSS ratio caused increase in the OFF-current of the PMDs, but did not affect the ON-current levels. This result demonstrates that highly-conductive current paths occur in the ON-state. The write-read-erase-read cycle test was operated > 10(5) times. And, the ON-retention time is largely dependent on the glycerol to PEDOT:PSS ratio and annealing temperature. In addition, AFM analysis on the G-PEDOT:PSS films to see how the surface morphology of G-PEDOT:PSS layer influences the retention time properties was carried out.

  3. Intracellular hydrolysis of short chain glycerides by rat small intestine in vitro and transfer of glycerol

    PubMed Central

    Howard, J.; Jackson, M. J.; Smyth, D. H.

    1970-01-01

    1. When triacetin, tripropionin and tributyrin are incubated with sacs of rat everted intestine, they enter the epithelial cells and are completely hydrolysed to free fatty acids and glycerol. 2. The distribution between the mucosal and serosal fluids of the glycerol released is very different from that of the fatty acid. Although both hydrolytic products are accumulated in the serosal fluid, a much higher fraction of the fatty acid appears in this compartment. 3. When glycerol is initially present in the mucosal fluid there is no evidence of its movement against a concentration gradient. 4. The results confirm the existence of a transport mechanism for fatty acids released intracellularly but do not require the hypothesis of a special mechanism for glycerol transfer. PMID:5500736

  4. The effect of additive compounds on glycerol-induced damage to human chondrocytes.

    PubMed

    Hahn, Joshua; Laouar, Leila; Elliott, Janet A W; Korbutt, Gregory S; Jomha, Nadr M

    2017-04-01

    High concentrations of cryoprotective agents are required for cryopreservation techniques such as vitrification. Glycerol is a common cryoprotective agent used in cryopreservation protocols but this agent is toxic at high concentrations. This work is an attempt to mitigate the toxic effects of high concentrations of glycerol on intact chondrocytes in human knee articular cartilage from total knee arthroplasty patients by simultaneous exposure to glycerol and a variety of additive compounds. The resulting cell viability in the cartilage samples as measured by membrane integrity staining showed that, in at least one concentration or in combination, all of the tested additive compounds (tetramethylpyrazine, ascorbic acid, chondroitin sulphate, glucosamine sulphate) were able to reduce the deleterious effects of glycerol exposure when examination of membrane integrity took place on a delayed time frame. The use of additive compounds to reduce cryoprotectant toxicity in articular cartilage may help improve cell recovery after cryopreservation.

  5. Acetylation of glycerol to biofuel additives over sulfated activated carbon catalyst.

    PubMed

    Khayoon, M S; Hameed, B H

    2011-10-01

    Oxygenated fuel additives can be produced by acetylation of glycerol. A 91% glycerol conversion with a selectivity of 38%, 28% and 34% for mono-, di- and triacetyl glyceride, respectively, was achieved at 120 °C and 3 h of reaction time in the presence of a catalyst derived from activated carbon (AC) treated with sulfuric acid at 85 °C for 4h to introduce acidic functionalities to its surface. The unique catalytic activity of the catalyst, AC-SA5, was attributed to the presence of sulfur containing functional groups on the AC surface, which enhanced the surface interaction between the glycerol molecule and acyl group of the acetic acid. The catalyst was reused in up to four consecutive batch runs and no significant decline of its initial activity was observed. The conversion and selectivity variation during the acetylation is attributed to the reaction time, reaction temperature, catalyst loading and glycerol to acetic acid molar ratio.

  6. Characterization of xanthan gum produced from glycerol by a mutant strain Xanthomonas campestris CCTCC M2015714.

    PubMed

    Wang, Zichao; Wu, Jianrong; Zhu, Li; Zhan, Xiaobei

    2017-02-10

    Xanthan gum was produced by a mutant strain X. campestris CCTCC M2015714 with glycerol as the sole carbon source. The monosaccharide composition and molar ratio of xanthan gum produced from glycerol are glucose: mannose: glucuronic acid=2.0:1.65:1.0. Meanwhile, chemical structure of xanthan gum produced from glycerol is similar to that of the commercial xanthan through FT-IR and NMR. Remarkably, the molecular weight of xanthan gum produced using our method (3.0±0.14×10(6)Da) is about half that of the commercial one (5.8±0.25×10(6)Da), and the consistency index (K) of which is less than 1/10 that of the commercial xanthan. This work paves the way for xanthan production from glycerol and is useful for studying the structure/application of xanthan gum.

  7. The optimization of biohydrogen production by bacteria using residual glycerol from biodiesel synthesis.

    PubMed

    Costa, Janaina B; Rossi, Daniele M; De Souza, Elisangela A; Samios, Dimitrios; Bregalda, Fernanda; do Carmo Ruaro Peralba, Maria; Flores, Simone H; Ayub, Marco Antônio Z

    2011-01-01

    In this research the production of hydrogen by Klebsiella pneumoniae BLb01 using residual glycerol discharged from a biodiesel fuel production plant was investigated. Klebsiella pneumoniae BLb01 was isolated from a bacteria-rich sludge of an upflow anaerobic sludge blanket reactor (UASB) of a soybean processing plant. A Plackett-Burman design (P-B) and Response Surface Methodology (RSM) were employed to determine the optimal condition for enhanced hydrogen production. The maximal hydrogen production, which was 45.0 mol % and with 98% of glycerol degradation, was achieved with the optimized medium with the following composition: 30 g L(-1) glycerol; 3 g L(-1) yeast ex tract 3 g L(-1) K(2)HPO(4); 1 g L(-1) KH(2)PO(4); temperature 39°C and pH 9.0. These results show the ability of this new strain of effectively converting residual glycerol into value-added energy products.

  8. Bioremediation of Parboiled Rice Effluent Supplemented with Biodiesel-Derived Glycerol Using Pichia pastoris X-33

    PubMed Central

    Gil de los Santos, Diego; Gil Turnes, Carlos; Rochedo Conceição, Fabricio

    2012-01-01

    This paper describes the use of Pichia pastoris X-33 as a bioremediator to reduce the chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and phosphorus (P-PO4   3−), after culture in parboiled rice effluent supplemented with p.a. glycerol or a glycerol by-product of the biodiesel industry. The greatest reduction in the COD (55%), TKN (45%), and P-PO4   3− (52%) of the effluent was observed in cultures of P. pastoris X-33 supplemented with 15 g ·L−1 of biodiesel-derived glycerol. Furthermore, the overall biomass yield was 2.1 g ·L−1. These data suggest that biodiesel-derived glycerol is an efficient carbon source for the bioremediation of parboiled rice effluent and biomass production. PMID:22919327

  9. Synthesis of a tetrasaccharide glycosyl glycerol. Precursor to glycolipids of Meiothermus taiwanensis ATCC BAA-400.

    PubMed

    Ren, Chien-Tai; Tsai, Yu-Hsuan; Yang, Yu-Liang; Zou, Wei; Wu, Shih-Hsiung

    2007-07-06

    Synthesis of a tetrasaccharide glycosyl glycerol, the core structure of glycoglycerolipid from Meiothermus taiwanensis ATCC BAA-400, was described. A one-pot glycosylation with three components was employed as a key step.

  10. Insect glycerol transporters evolved by functional co-option and gene replacement

    PubMed Central

    Finn, Roderick Nigel; Chauvigné, François; Stavang, Jon Anders; Belles, Xavier; Cerdà, Joan

    2015-01-01

    Transmembrane glycerol transport is typically facilitated by aquaglyceroporins in Prokaryota and Eukaryota. In holometabolan insects however, aquaglyceroporins are absent, yet several species possess polyol permeable aquaporins. It thus remains unknown how glycerol transport evolved in the Holometabola. By combining phylogenetic and functional studies, here we show that a more efficient form of glycerol transporter related to the water-selective channel AQP4 specifically evolved and multiplied in the insect lineage, resulting in the replacement of the ancestral branch of aquaglyceroporins in holometabolan insects. To recapitulate this evolutionary process, we generate specific mutants in distantly related insect aquaporins and human AQP4 and show that a single mutation in the selectivity filter converted a water-selective channel into a glycerol transporter at the root of the crown clade of hexapod insects. Integration of phanerozoic climate models suggests that these events were associated with the emergence of complete metamorphosis and the unparalleled radiation of insects. PMID:26183829

  11. Insect glycerol transporters evolved by functional co-option and gene replacement.

    PubMed

    Finn, Roderick Nigel; Chauvigné, François; Stavang, Jon Anders; Belles, Xavier; Cerdà, Joan

    2015-07-17

    Transmembrane glycerol transport is typically facilitated by aquaglyceroporins in Prokaryota and Eukaryota. In holometabolan insects however, aquaglyceroporins are absent, yet several species possess polyol permeable aquaporins. It thus remains unknown how glycerol transport evolved in the Holometabola. By combining phylogenetic and functional studies, here we show that a more efficient form of glycerol transporter related to the water-selective channel AQP4 specifically evolved and multiplied in the insect lineage, resulting in the replacement of the ancestral branch of aquaglyceroporins in holometabolan insects. To recapitulate this evolutionary process, we generate specific mutants in distantly related insect aquaporins and human AQP4 and show that a single mutation in the selectivity filter converted a water-selective channel into a glycerol transporter at the root of the crown clade of hexapod insects. Integration of phanerozoic climate models suggests that these events were associated with the emergence of complete metamorphosis and the unparalleled radiation of insects.

  12. Glycerol conversion into value added chemicals over bimetallic catalysts in supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Hidayati, Luthfiana N.; Sudiyarmanto, Adilina, Indri B.

    2017-01-01

    Development of alternative energy from biomass encourage the experiments and production of biodiesel lately. Biodiesel industries widely expand because biodiesel as substitute of fossil fuel recognized as promising renewable energy. Glycerol is a byproduct of biodiesel production, which is resulted 10% wt average every production. Meanwhile, carbon dioxide is a gas that is very abundant amount in the atmosphere. Glycerol and carbon dioxide can be regarded as waste, possibly will produce value-added chemical compounds through chemically treated. In this preliminary study, conversion of glycerol and carbon dioxide using bimetallic catalyst Ni-Sn with various catalyst supports : MgO, γ-Al2O3, and hydrotalcite. Catalysts which have been prepared, then physically characterized by XRD, surface area and porosity analysis, and thermal gravity analysis. Catalytic test performance using supercritical carbon dioxide conditions. Furthermore, the products were analyzed by GC. The final product mostly contained of propylene glycol and glycerol carbonate.

  13. Elevated 3-hydroxypropionaldehyde production from glycerol using a Citrobacter freundii mutant.

    PubMed

    West, Thomas P; Peterson, Jessica L

    2014-01-01

    A mutant strain of Citrobacter freundii capable of elevated 3-hydroxypropionaldehyde production from glycerol was isolated using chemical mutagenesis and a screening protocol. The protocol involved screening mutagenized bacterial cells on solid minimal medium containing 5 % (v/v) glycerol. Colonies were picked onto duplicate solid minimal medium plates and one plate was stained with 1 % (w/v) phloroglucinol. Those colonies staining red were further screened and a mutant, HPAO-1, was identified. The mutant strain produced a several-fold higher 3-hydroxypropionaldehyde concentration than did the parent strain when grown on 5 % (v/v) glycerol. The ratio of culture volume to flask volume influenced 3-hydroxypropionaldehyde production by the mutant cells compared to the parent cells. Aldehyde production was highest when the mutant strain was grown on 5 % (v/v) glycerol at a ratio of culture volume to flask volume of 1:3 or 1:12.5.

  14. Optimization of fermentation condition favoring butanol production from glycerol by Clostridium pasteurianum DSM 525.

    PubMed

    Sarchami, Tahereh; Johnson, Erin; Rehmann, Lars

    2016-05-01

    Butanol is a promising biofuel and valuable platform chemical that can be produced through fermentative conversion of glycerol. The initial fermentation conditions for butanol production from pure glycerol by Clostridium pasteurianum DSM 525 were optimized via a central composite design. The effect of inoculum age, initial cell density, initial pH of medium and temperature were quantified and a quadratic model was able to predict butanol yield as a function of all four investigated factors. The model was confirmed through additional experiments and via analysis of variance (ANOVA). Subsequently, numerical optimization was used to maximize the butanol yield within the experimental range. Based on these results, batch fermentations in a 7 L bioreactor were performed using pure and crude (residue from biodiesel production) glycerol as substrates at optimized conditions. A butanol yield of 0.34 mole(butanol) mole(-1)(glycerol) was obtained indicating the suitability of this feedstock for fermentative butanol production.

  15. Converting crude glycerol derived from yellow grease to lipids through yeast fermentation.

    PubMed

    Liang, Yanna; Cui, Yi; Trushenski, Jesse; Blackburn, James W

    2010-10-01

    Cryptococcus curvatus, an oleaginous yeast was observed to grow on crude glycerol derived from yellow grease. When cultured in a one-stage fed-batch process wherein crude glycerol and nitrogen source were fed intermittently for 12 days, the final biomass density and lipid content were 31.2 g/l and 44.2%, respectively. When cultured in a two-stage fed-batch operation wherein crude glycerol was supplemented at different time points while nitrogen source addition was discontinued at the middle of the experiment, the biomass density was 32.9 g/l and the lipid content was 52% at the end of 12 days. Compared with other oil feedstocks for biodiesel production, lipid accumulated by C. curvatus grown on glycerol has high concentration of monounsaturated fatty acid, which makes it an excellent source for biodiesel use.

  16. Zeolitic Core@Shell Adsorbents for the Selective Removal of Free Glycerol from Crude Biodiesel.

    PubMed

    Masoumifard, Nima; Arnal, Pablo M; Kaliaguine, Serge; Kleitz, Freddy

    2015-06-22

    Selective adsorption of free glycerol from crude biodiesel was investigated by using mesoporous silica spheres coated with a thin shell of microporous silicalite-1. A polycrystalline silicalite-1 shell was formed upon first covering the external surfaces of various core templates with discrete silicalite-1 nanocrystals, and this was followed by short hydrothermal treatment to ensure shell uniformity. Batch glycerol adsorption experiments were conducted to evaluate the ability of the sorbents to remove free glycerol selectively from crude biodiesel mixtures at various temperatures, also in comparison to that of conventional sorbents, for example, bare mesoporous silica gel spheres and zeolites. The silicalite-1 shell provided a microporous membrane that hindered the diffusion of fatty acid methyl esters into the mesopores of the composite sorbent, whereas the large pore volume of the mesoporous core enabled multilayer glycerol adsorption; this ultimately substantially enhanced the performance in terms of purification yield and adsorption capacity.

  17. Kinetic analysis of dihydroxyacetone production from crude glycerol by immobilized cells of Gluconobacter oxydans MTCC 904.

    PubMed

    Dikshit, Pritam Kumar; Moholkar, Vijayanand S

    2016-09-01

    The present study has investigated kinetic features of bioconversion of biodiesel-derived crude glycerol to dihydroxyacetone with immobilized Gluconobacter oxydans cells using modified Haldane substrate-inhibition model. The results have been compared against free cells and pure glycerol. Relative variations in the kinetic parameters KS, KI, Vmax, n and X reveal that immobilized G. oxydans cells (on PU foam substrate) with crude glycerol as substrate give higher order of inhibition (n) and lower maximum reaction velocities (Vmax). These results are essentially implications of substrate transport restrictions across immobilization matrix, which causes retention of substrate in the matrix and reduction in fractional available substrate (X) for the cells. This causes reduction in both KS (substrate concentration at Vmax/2) and KI (inhibition constant) as compared to free cells. For immobilized cells, substrate concentration (Smax) corresponding to Vmax is practically same for both pure and crude glycerol as substrate.

  18. Cyanamide mediated synthesis under plausible primitive earth conditions. VI - The synthesis of glycerol and glycerophosphates

    NASA Technical Reports Server (NTRS)

    Epps, D. E.; Nooner, D. W.; Eichberg, J.; Sherwood, E.; Oro, J.

    1979-01-01

    The formation of glycerol occurs when a solution of DL-glyceraldehyde is heated in the presence of hydrogen sulfide at room temperature. DL-glyceraldehyde and dihydroxyacetone treated with hydrazine, as well as DL-glyceraldehyde incubated with formaldehyde are also partially converted to glycerol. The yields of the above reactions are from approximately 1% to about 3%. The formation of glycerophosphates occurs when glycerol is heated with ammonium dihydrogen phosphate and either urea or cyanamide. The yield of glycerophosphates is about 30%, most of which is sn-glycero-1(3)-phosphate. These findings indicate that glycerol and sn-glycero-3-phosphate, which are moieties of glycerolipids, could have been formed under conditions which may have prevailed on the primitive earth.

  19. Preparation and use of photocatalytically active segmented Ag|ZnO and coaxial TiO2-Ag nanowires made by templated electrodeposition.

    PubMed

    Maijenburg, A Wouter; Rodijk, Eddy J B; Maas, Michiel G; Ten Elshof, Johan E

    2014-05-02

    Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 µm were made by templated electrodeposition within the pores of polycarbonate track-etched (PCTE) or anodized aluminum oxide (AAO) membranes, respectively. In the photocatalytic experiments, the ZnO and TiO2 phases acted as photoanodes, and Ag as cathode. No external circuit is needed to connect both electrodes, which is a key advantage over conventional photo-electrochemical cells. For making segmented Ag|ZnO nanowires, the Ag salt electrolyte was replaced after formation of the Ag segment to form a ZnO segment attached to the Ag segment. For making coaxial TiO2-Ag nanowires, a TiO2 gel was first formed by the electrochemically induced sol-gel method. Drying and thermal annealing of the as-formed TiO2 gel resulted in the formation of crystalline TiO2 nanotubes. A subsequent Ag electrodeposition step inside the TiO2 nanotubes resulted in formation of coaxial TiO2-Ag nanowires. Due to the combination of an n-type semiconductor (ZnO or TiO2) and a metal (Ag) within the same nanowire, a Schottky barrier was created at the interface between the phases. To demonstrate the photocatalytic activity of these nanowires, the Ag|ZnO nanowires were used in a photocatalytic experiment in which H2 gas was detected upon UV illumination of the nanowires dispersed in a methanol/water mixture. After 17 min of illumination, approximately 0.2 vol% H2 gas was detected from a suspension of ~0.1 g of Ag|ZnO nanowires in a 50 ml 80 vol% aqueous methanol solution.

  20. Preparation and Use of Photocatalytically Active Segmented Ag|ZnO and Coaxial TiO2-Ag Nanowires Made by Templated Electrodeposition

    PubMed Central

    Maijenburg, A. Wouter; Rodijk, Eddy J.B.; Maas, Michiel G.; ten Elshof, Johan E.

    2014-01-01

    Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 µm were made by templated electrodeposition within the pores of polycarbonate track-etched (PCTE) or anodized aluminum oxide (AAO) membranes, respectively. In the photocatalytic experiments, the ZnO and TiO2 phases acted as photoanodes, and Ag as cathode. No external circuit is needed to connect both electrodes, which is a key advantage over conventional photo-electrochemical cells. For making segmented Ag|ZnO nanowires, the Ag salt electrolyte was replaced after formation of the Ag segment to form a ZnO segment attached to the Ag segment. For making coaxial TiO2-Ag nanowires, a TiO2 gel was first formed by the electrochemically induced sol-gel method. Drying and thermal annealing of the as-formed TiO2 gel resulted in the formation of crystalline TiO2 nanotubes. A subsequent Ag electrodeposition step inside the TiO2 nanotubes resulted in formation of coaxial TiO2-Ag nanowires. Due to the combination of an n-type semiconductor (ZnO or TiO2) and a metal (Ag) within the same nanowire, a Schottky barrier was created at the interface between the phases. To demonstrate the photocatalytic activity of these nanowires, the Ag|ZnO nanowires were used in a photocatalytic experiment in which H2 gas was detected upon UV illumination of the nanowires dispersed in a methanol/water mixture. After 17 min of illumination, approximately 0.2 vol% H2 gas was detected from a suspension of ~0.1 g of Ag|ZnO nanowires in a 50 ml 80 vol% aqueous methanol solution. PMID:24837535

  1. Lasting antibacterial activities of Ag-TiO2/Ag/a-TiO2 nanocomposite thin film photocatalysts under solar light irradiation.

    PubMed

    Akhavan, O

    2009-08-01

    Photodegradation of Escherichia coli bacteria in presence of Ag-TiO(2)/Ag/a-TiO(2) nanocomposite film with an effective storage of silver nanoparticles was investigated in the visible and the solar light irradiations. The nanocomposite film was synthesized by sol-gel deposition of 30 nm Ag-TiO(2) layer on approximately 200 nm anatase(a-)TiO(2) film previously doped by silver nanoparticles. Both Ag/a-TiO(2) and Ag-TiO(2)/Ag/a-TiO(2) films were transparent with a SPR absorption band at 412 nm. Depth profile X-ray photoelectron spectroscopy showed metallic silver nanoparticles with diameter of 30 nm and fcc crystalline structure were self-accumulated on the film surface at depth of 5 nm of the TiO(2) layer and also at the interface of the Ag-TiO(2) and a-TiO(2) films (at depth of 30 nm). Both OH(-) bounds and H(2)O contents were concentrated on the film surface and at the interface, as a profit in releasing more ionic (not metallic) silver nanoparticles. Antibacterial activity of the nanocomposite film against E. coli bacteria was 5.1 times stronger than activity of the a-TiO(2), in dark. Photo-antibacterial activity of the nanocomposite film exposed by the solar light was measured 1.35 and 6.90 times better than activity of the Ag/a-TiO(2) and a-TiO(2), respectively. The main mechanism for silver ion releasing was inter-diffusion of water and silver nanoparticles through pores of the TiO(2) layer. Durability of the nanocomposite film was at least 11 times higher than the Ag/a-TiO(2) film. Therefore, the Ag-TiO(2)/Ag/a-TiO(2) photocatalyst can be nominated as one of the effective and long-lasting antibacterial nanocomposite materials.

  2. Glass polymorphism in glycerol-water mixtures: I. A computer simulation study.

    PubMed

    Jahn, David A; Wong, Jessina; Bachler, Johannes; Loerting, Thomas; Giovambattista, Nicolas

    2016-04-28

    We perform out-of-equilibrium molecular dynamics (MD) simulations of water-glycerol mixtures in the glass state. Specifically, we study the transformations between low-density (LDA) and high-density amorphous (HDA) forms of these mixtures induced by compression/decompression at constant temperature. Our MD simulations reproduce qualitatively the density changes observed in experiments. Specifically, the LDA-HDA transformation becomes (i) smoother and (ii) the hysteresis in a compression/decompression cycle decreases as T and/or glycerol content increase. This is surprising given the fast compression/decompression rates (relative to experiments) accessible in MD simulations. We study mixtures with glycerol molar concentration χ(g) = 0-13% and find that, for the present mixture models and rates, the LDA-HDA transformation is detectable up to χ(g) ≈ 5%. As the concentration increases, the density of the starting glass (i.e., LDA at approximately χ(g) ≤ 5%) rapidly increases while, instead, the density of HDA remains practically constant. Accordingly, the LDA state and hence glass polymorphism become inaccessible for glassy mixtures with approximately χ(g) > 5%. We present an analysis of the molecular-level changes underlying the LDA-HDA transformation. As observed in pure glassy water, during the LDA-to-HDA transformation, water molecules within the mixture approach each other, moving from the second to the first hydration shell and filling the first interstitial shell of water molecules. Interestingly, similar changes also occur around glycerol OH groups. It follows that glycerol OH groups contribute to the density increase during the LDA-HDA transformation. An analysis of the hydrogen bond (HB)-network of the mixtures shows that the LDA-HDA transformation is accompanied by minor changes in the number of HBs of water and glycerol. Instead, large changes in glycerol and water coordination numbers occur. We also perform a detailed analysis of the effects that

  3. Mapping and cloning of gldA, the structural gene of the Escherichia coli glycerol dehydrogenase.

    PubMed Central

    Truniger, V; Boos, W

    1994-01-01

    gldA, the structural gene for the NAD(+)-dependent glycerol dehydrogenase, was mapped at 89.2 min on the Escherichia coli linkage map, cotransducible with, but not adjacent to, the glpFKX operon encoding the proteins for the uptake and phosphorylation of glycerol. gldA was cloned, and its position on the physical map of E. coli was determined. The expression of gldA was induced by hydroxyacetone under stationary-phase growth conditions. Images PMID:8132480

  4. Models for the biological production of glycerol and biosurfactants from potato-processing industry residuals

    SciTech Connect

    Polman, K.; Bala, G.A.; St. Clair, P.

    1995-12-31

    The fermentative production of valuable chemicals from biomass-derived substrates (e.g., glucose) represents the historical essence of industrial biotechnology. In the past, the capabilities of microorganisms to produce useful chemicals have been, at best, sporadically utilized. The primary products produced biotechnologically today are antibiotics and ethanol (for fuel and beverage uses). Many years ago, glycerol (also known as glycerin or glycerine) was produced at an industrial scale by fermentative means. Such production was stimulated by increased demand for glycerol and diversion of petroleum resources during wartime. Biotechnological production of glycerol ceased during peacetime, because the undeveloped and inefficient biotechnological processes that were used could not compete with inexpensive petroleum and natural feedstocks and the efficient and well developed methods by which to convert them to commodity chemicals. Industrial glycerol production by biological conversion of sugar has not occurred since that time. However, several factors, including the historical uncertainty of petroleum price and supply, the demand for environmentally safe industrial processes, and the vast development and improvement of bioprocess technology, suggest that the time for taking advantage of bioprocesses that produce marketable chemicals is near. Glycerol is a good candidate for such a chemical, because it is biologically produced from glucose in good yield (0.5 g glycerol/g glucose), the market is very large (> 140 million kg consumed/yr in the US), and future market growth is predicted to be good because of the widespread usage of glycerol and its historically strong market. Based on this, recent research has involved developing patentable technologies for the conversion of corn starch to glycerol; these efforts have progressed to the pilot plant scale.

  5. Enhanced enzymatic activity of glycerol-3-phosphate dehydrogenase from the cryophilic Saccharomyces kudriavzevii.

    PubMed

    Oliveira, Bruno M; Barrio, Eladio; Querol, Amparo; Pérez-Torrado, Roberto

    2014-01-01

    During the evolution of the different species classified within the Saccharomyces genus, each one has adapted to live in different environments. One of the most important parameters that have influenced the evolution of Saccharomyces species is the temperature. Here we have focused on the study of the ability of certain species as Saccharomyces kudriavzevii to grow at low temperatures, in contrast to Saccharomyces cerevisiae. We observed that S. kudriavzevii strains isolated from several regions are able to synthesize higher amounts of glycerol, a molecule that has been shown to accumulate in response to freeze and cold stress. To explain this observation at the molecular level we studied the expression of glycerol biosynthetic pathway genes and we observed a higher expression of GPD1 gene in S. kudriavzevii compared to S. cerevisiae in micro-vinification conditions. We observed higher enzymatic activity of Gpd1p in S. kudriavzevii in response to osmotic and cold stress. Also, we determined that S. kudriavzevii Gpd1p enzyme presents increased catalytic properties that will contribute to increase glycerol production. Finally, we evaluated the glycerol production with S. cerevisiae, S. kudriavzevii or a recombinant Gpd1p variant in the same background and observed that the S. kudriavzevii enzyme produced increased glycerol levels at 12 or 28°C. This suggests that glycerol is increased in S. kudriavzevii mainly due to increased V max of the Gpd1p enzyme. All these differences indicate that S. kudriavzevii has changed the metabolism to promote the branch of the glycolytic pathway involved in glycerol production to adapt to low temperature environments and maintain the NAD(+)/NADH ratio in alcoholic fermentations. This knowledge is industrially relevant due to the potential use, for example, of S. cerevisiae-S. kudriavzevii hybrids in the wine industry where glycerol content is an important quality parameter.

  6. Fracture phenomena in an isotonic salt solution during freezing and their elimination using glycerol.

    PubMed

    Gao, D Y; Lin, S; Watson, P F; Critser, J K

    1995-06-01

    Thermal stress and consequent fracture in frozen organs or cell suspensions have been proposed to be two causes of cell cryoinjury. A specific device was developed to study the thermal stress and the fracture phenomena during a slow cooling process of isotonic NaCl solutions with different concentrations of glycerol (cryoprotectant) in a cylindrical tube. It was shown from the experimental results that glycerol significantly influenced the solidification process of the ternary solutions and reduced the thermal stress. The higher the initial glycerol concentration, the lower the thermal stress in the frozen solutions. Glycerol concentrations over 0.3 M were sufficient to eliminate the fracture of the frozen solutions under the present experimental conditions. To explain the action of glycerol in reducing the thermal stress and preventing the ice fracture, a further study on ice crystal formation and growth of ice in these solutions was undertaken using cryomicroscopy. It is known from previous studies that an increase of initial glycerol concentration reduced frozen fraction of water in the solution at any given low temperature due to colligative properties of solution, which reduced the total ice volume expansion during water solidification. The present cryomicroscopic investigation showed that under a fixed cooling condition the different initial glycerol concentrations induced the different microstructures of the frozen solutions at not only a given low temperature but also a given frozen fraction of water. It has been known that ice volume expansion during solidification is a major factor causing the thermal stress and the interior microstructure is critical for the mechanical strength of a solid. Therefore, functions of glycerol in reducing the total ice volume expansion during water solidification and in influencing interior microstructure of the ice may contribute to reduce the thermal stress and prevent the fracture in the frozen solutions.

  7. Chemical mechanical planarization of copper/polyimide damascene structure with glycerol-based slurry

    NASA Astrophysics Data System (ADS)

    Permana, David

    This thesis describes the results of an investigation of the Chemical Mechanical Planarization (CMP) of copper and polyimide films with glycerol-based (high viscosity) slurry. A physical planarization model of the polyimide CMP carried out with high viscosity slurry has been developed, with the removal mechanism was primarily being mechanical abrasion. The high viscosity slurry minimizes the impact between the abrasive and polyimide film, thus reducing scratching and damage. However, the scratch density is also strongly dependent on the pad, with soft pads leading to less scratching. The use of BTAH in forming a passivating film on copper surface during CMP was proven to be effective. The effect of glycerol on the passivation of copper was found to be insignificant. The addition of glycerol in the slurry results in a unique CMP removal rate behavior for both copper and polyimide. The removal rate increases with increasing glycerol concentration and reaches a maximum value at 30 vol% glycerol due to particle aggregation and decreases at higher glycerol concentrations due to reduction in the frictional forces between the abrasive particles and the film surface. The possibility of implementing the unique removal rate behavior on the planarization of copper/polyimide damascene structure was also investigated. Dual-step polish process was designed by utilizing the high removal rate with the slurry containing 30 vol% of glycerol, followed by the slurry containing 50 vol% glycerol for over-polish step process. The high viscosity slurry was to protect the soft polymer film as the metal film is abraded away. It was also found that high viscosity slurry induces lower dishing and erosion on the pattern structure.

  8. Synthesis of sn-glycerol 3-phosphate, a key precursor of membrane lipids, in Bacillus subtilis.

    PubMed Central

    Morbidoni, H R; de Mendoza, D; Cronan, J E

    1995-01-01

    The Bacillus subtilis gpsA gene was cloned by complementation of an Escherichia coli gpsA strain auxotrophic for sn-glycerol 3-phosphate. The gene was sequenced and found to encode an NAD(P)H-dependent dihydroxyacetone phosphate reductase with a deduced molecular mass of 39.5 kDa. The deduced amino acid sequence showed strong conservation with that of the E. coli homolog and to other procaryotic and eucaryotic dihydroxyacetone phosphate reductases. The physical location of gpsA on the B. subtilis chromosome was at about 200 degrees. Disruption of the chromosomal gpsA gene yielded B. subtilis strains auxotrophic for glycerol, indicating that the gpsA gene product is responsible for synthesis of the sn-glycerol 3-phosphate required for phospholipid synthesis. We also found that transformation of the classical B. subtilis glycerol auxotrophs with a gpsA-containing genomic fragment yielded transformants that grew in the absence of glycerol. In agreement with prior work, our attempts to determine the reductase activity in B. subtilis extracts were unsuccessful. However, expression of the B. subtilis gpsA gene in E. coli gave reductase activity that was only slightly inhibited by sn-glycerol 3-phosphate. Since the E. coli GpsA dihydroxyacetone phosphate reductase is very sensitive to allosteric inhibition by sn-glycerol 3-phosphate, these results indicate that the B. subtilis gpsA-encoded reductase differs from that of E. coli. It seems that B. subtilis regulates sn-glycerol 3-phosphate synthesis at the level of gene expression rather than through the E. coli mechanism of strong allosteric inhibition of an enzyme produced in excess. PMID:7592341

  9. Dependence of NO recombination dynamics in horse myoglobin on solution glycerol content

    SciTech Connect

    Shreve, A.P.; Franzen, S.; Simpson, M.C.; Dyer, R.B.

    1999-09-16

    The recombination dynamics of NO with horse heart myoglobin (Mb) following photolysis with a 570 nm excitation pulse were measured by time-resolved absorption with 250 fs temporal resolution. These measurements were carried out in room-temperature solutions in which the glycerol concentration was varied from 0 to 90% (w/v). The recombination of NO is nonsingle exponential in all cases,m but becomes faster as the glycerol concentration is increased. The interpretation of these results is aided by a maximum entropy analysis to determine a distribution of rate processes consistent with the data. This analysis suggests that in buffer there are two dominant rate processes for NO recombination on the subnanosecond time scale, one at {approx}10 ps and one at {approx}200 ps. The dominant effect of increasing glycerol content is to increase the amplitude of the fast process, with no corresponding significant change in rate, and to decrease the amplitude of the slow process, with no corresponding significant change in rate, and to decrease the amplitude of the slow process, but with a corresponding increase in rate. These results are consistent with a photodissociation process in which photolyzed NO partitions immediately between two distinct populations, one of which has a rapid and the other of which has a slower recombination. The rate of the rapid recombination is independent of glycerol concentration, and therefore decoupled from any protein relaxation process influenced by glycerol, while that of the slower recombination increases at higher glycerol concentration. Further, the partitioning between these two populations also depends on glycerol content, with the relative amplitude of the faster recombination process increasing as the glycerol content is increased. Interpretation of these observations in terms of ligand trajectories following photodissociation, and possible connections of these results with both infrared and crystallographic studies of photodissociated

  10. 3-Hydroxypropionaldehyde guided glycerol feeding strategy in aerobic 1,3-propanediol production by Klebsiella pneumoniae.

    PubMed

    Hao, Jian; Lin, Rihui; Zheng, Zongming; Sun, Yan; Liu, Dehua

    2008-12-01

    3-Hydroxypropionaldehyde (3-HPA) is a toxic intermediary metabolite in the biological route of 1,3-propanediol biosynthesis from glycerol. 3-HPA accumulated in culture medium would arouse an irreversible cessation of the fermentation process. The role of substrate (glycerol) on 3-HPA accumulation in aerobic fermentation was investigated in this paper. 1,3-Propanediol oxidoreductase and glycerol dehydratase, two key enzyme catalyzing reactions of 3-HPA formation and consumption, were sensitive to high concentration of 3-HPA. When the concentration of 3-HPA increased to a higher level in medium (ac 10 mmol/L), the activity of 1,3-propanediol oxidoreductase in cell decreased correspondingly, which led to decrease of the 3-HPA conversion rate, then the 3-HPA concentration increasing was accelerated furthermore. 3-HPA accumulation in culture medium was triggered by this positive feedback mechanism. In the cell exponential growth phase, the reaction catalyzed by 1,3-propanediol oxidoreductase was the rate limiting step in 1,3-propanediol production. The level of 3-HPA in culture medium could be controlled by the substrate (glycerol) concentration, and lower level of glycerol could avoid 3-HPA accumulating to a high, lethal concentration. In fed batch fermentation, under the condition of initial glycerol concentration 30 g/L, and keeping glycerol concentration lower than 7-8 g/L in cell exponential growth phase, 3-HPA accumulation could not be incurred. Based on this result, a glycerol feeding strategy was set up in fed batch fermentation. Under the optimized condition, 50.1 g/L of 1,3-propanediol was produced in 24 h, and 73.1 g/L of final 1,3-propanediol concentration was obtained in 54 h.

  11. Adaptation of acidogenic sludge to increasing glycerol concentrations for biohydrogen production.

    PubMed

    Tapia-Venegas, E; Cabrol, L; Brandhoff, B; Hamelin, J; Trably, E; Steyer, J P; Ruiz-Filippi, G

    2015-10-01

    Hydrogen is a promising alternative as an energetic carrier and its production by dark fermentation from wastewater has been recently proposed, with special attention to crude glycerol as potential substrate. In this study, two different feeding strategies were evaluated for replacing the glucose substrate by glycerol substrate: a one-step strategy (glucose was replaced abruptly by glycerol) and a step-by-step strategy (progressive decrease of glucose concentration and increase of glycerol concentration from 0 to 5 g L(-1)), in a continuous stirred tank reactor (12 h of hydraulic retention time (HRT), pH 5.5, 35 °C). While the one-step strategy led to biomass washout and unsuccessful H2 production, the step-by-step strategy was efficient for biomass adaptation, reaching acceptable hydrogen yields (0.4 ± 0.1 molH2 mol(-1) glycerol consumed) around 33 % of the theoretical yield independently of the glycerol concentration. Microbial community structure was investigated by single-strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) fingerprinting techniques, targeting either the total community (16S ribosomal RNA (rRNA) gene) or the functional Clostridium population involved in H2 production (hydA gene), as well as by 454 pyrosequencing of the total community. Multivariate analysis of fingerprinting and pyrosequencing results revealed the influence of the feeding strategy on the bacterial community structure and suggested the progressive structural adaptation of the community to increasing glycerol concentrations, through the emergence and selection of specific species, highly correlated to environmental parameters. Particularly, this work highlighted an interesting shift of dominant community members (putatively responsible of hydrogen production in the continuous stirred tank reactor (CSTR)) according to the gradient of glycerol proportion in the feed, from the family Veillonellaceae to the genera Prevotella and

  12. Dysregulation of the peripheral and adipose tissue endocannabinoid system in human abdominal obesity.

    PubMed

    Blüher, Matthias; Engeli, Stefan; Klöting, Nora; Berndt, Janin; Fasshauer, Mathias; Bátkai, Sándor; Pacher, Pál; Schön, Michael R; Jordan, Jens; Stumvoll, Michael

    2006-11-01

    The endocannabinoid system has been suspected to contribute to the association of visceral fat accumulation with metabolic diseases. We determined whether circulating endocannabinoids are related to visceral adipose tissue mass in lean, subcutaneous obese, and visceral obese subjects (10 men and 10 women in each group). We further measured expression of the cannabinoid type 1 (CB(1)) receptor and fatty acid amide hydrolase (FAAH) genes in paired samples of subcutaneous and visceral adipose tissue in all 60 subjects. Circulating 2-arachidonoyl glycerol (2-AG) was significantly correlated with body fat (r = 0.45, P = 0.03), visceral fat mass (r = 0.44, P = 0.003), and fasting plasma insulin concentrations (r = 0.41, P = 0.001) but negatively correlated to glucose infusion rate during clamp (r = 0.39, P = 0.009). In visceral adipose tissue, CB(1) mRNA expression was negatively correlated with visceral fat mass (r = 0.32, P = 0.01), fasting insulin (r = 0.48, P < 0.001), and circulating 2-AG (r = 0.5, P < 0.001), whereas FAAH gene expression was negatively correlated with visceral fat mass (r = 0.39, P = 0.01) and circulating 2-AG (r = 0.77, P < 0.001). Our findings suggest that abdominal fat accumulation is a critical correlate of the dysregulation of the peripheral endocannabinoid system in human obesity. Thus, the endocannabinoid system may represent a primary target for the treatment of abdominal obesity and associated metabolic changes.

  13. The Volitional Nature of Nicotine Exposure Alters Anandamide and Oleoylethanolamide Levels in the Ventral Tegmental Area

    PubMed Central

    Buczynski, Matthew W; Polis, Ilham Y; Parsons, Loren H

    2013-01-01

    Cannabinoid-1 receptors (CB1) have an important role in nicotine reward and their function is disrupted by chronic nicotine exposure, suggesting nicotine-induced alterations in endocannabinoid (eCB) signaling. However, the effects of nicotine on brain eCB levels have not been rigorously evaluated. Volitional intake of nicotine produces physiological and behavioral effects distinct from forced drug administration, although the mechanisms underlying these effects are not known. This study compared the effects of volitional nicotine self-administration (SA) and forced nicotine exposure (yoked administration (YA)) on levels of eCBs and related neuroactive lipids in the ventral tegmental area (VTA) and other brain regions. Brain lipid levels were indexed both by in vivo microdialysis in the VTA and lipid extractions from brain tissues. Nicotine SA, but not YA, reduced baseline VTA dialysate oleoylethanolamide (OEA) levels relative to nicotine-naïve controls, and increased anandamide (AEA) release during nicotine intake. In contrast, all nicotine exposure paradigms increased VTA dialysate 2-arachidonoyl glycerol (2-AG) levels. Thus, nicotine differentially modulates brain lipid (2-AG, AEA, and OEA) signaling, and these modulations are influenced by the volitional nature of the drug exposure. Corresponding bulk tissue analysis failed to identify these lipid changes. Nicotine exposure had no effect on fatty acid amide hydrolase activity in the VTA, suggesting that changes in AEA and OEA signaling result from alterations in their nicotine-induced biosynthesis. Both CB1 (by AEA and 2-AG) and non-CB1 (by OEA) targets can alter the excitability and activity of the dopaminergic neurons in the VTA. Collectively, these findings implicate disrupted lipid signaling in the motivational effects of nicotine. PMID:23169348

  14. Cannabinoid receptor agonists modulate calcium channels in rat retinal Müller cells.

    PubMed

    Yang, W; Li, Q; Wang, S-Y; Gao, F; Qian, W-J; Li, F; Ji, M; Sun, X-H; Miao, Y; Wang, Z

    2016-01-28

    While activation of cannabinoid CB1 receptor (CB1R) regulates a variety of retinal neuronal functions by modulating ion channels in these cells, effect of activated cannabinoid receptors on Ca(2+) channels in retinal Müller cells is still largely unknown. In the present work we show that three subunits of T-type Ca(2+) channels, CaV3.1, CaV3.2 and CaV3.3, as well as one subunit of L-type Ca(2+) channels, CaV1.2, were expressed in rat Müller cells by immunofluorescent staining. Consistently, nimodipine- and mibefradil-sensitive Na(+) currents through L- and T-type Ca(2+) channels could be recorded electrophysiologically. The cannabinoid receptor agonist WIN55212-2 significantly suppressed Ca(2+) channel currents, mainly the T-type one, in acutely isolated rat Müller cells in a dose-dependent manner, with an IC50 of 3.98μM. The WIN55212-2 effect was not blocked by AM251/SR141716, specific CB1R antagonists. Similar suppression of the currents was observed when anandamide (AEA) and 2-arachidonoyl glycerol (2-AG), endogenous ligands of cannabinoid receptors, were applied. Moreover, even though CB2 receptors (CB2Rs) were expressed in rat Müller cells, the effects of WIN55212-2 and 2-AG on Ca(2+) channel currents were not blocked by AM630, a selective CB2R antagonist. However, the effect of AEA could be partially rescued by AM630. These results suggest that WIN55212-2 and 2-AG receptor-independently suppressed the Ca(2+) channel currents in Müller cells, while AEA suppressed the currents partially through CB2Rs. The existence of receptor-dependent and -independent mechanisms suggests that cannabinoids may modulate Müller cell functions through multiple pathways.

  15. The volitional nature of nicotine exposure alters anandamide and oleoylethanolamide levels in the ventral tegmental area.

    PubMed

    Buczynski, Matthew W; Polis, Ilham Y; Parsons, Loren H

    2013-03-01

    Cannabinoid-1 receptors (CB(1)) have an important role in nicotine reward and their function is disrupted by chronic nicotine exposure, suggesting nicotine-induced alterations in endocannabinoid (eCB) signaling. However, the effects of nicotine on brain eCB levels have not been rigorously evaluated. Volitional intake of nicotine produces physiological and behavioral effects distinct from forced drug administration, although the mechanisms underlying these effects are not known. This study compared the effects of volitional nicotine self-administration (SA) and forced nicotine exposure (yoked administration (YA)) on levels of eCBs and related neuroactive lipids in the ventral tegmental area (VTA) and other brain regions. Brain lipid levels were indexed both by in vivo microdialysis in the VTA and lipid extractions from brain tissues. Nicotine SA, but not YA, reduced baseline VTA dialysate oleoylethanolamide (OEA) levels relative to nicotine-naïve controls, and increased anandamide (AEA) release during nicotine intake. In contrast, all nicotine exposure paradigms increased VTA dialysate 2-arachidonoyl glycerol (2-AG) levels. Thus, nicotine differentially modulates brain lipid (2-AG, AEA, and OEA) signaling, and these modulations are influenced by the volitional nature of the drug exposure. Corresponding bulk tissue analysis failed to identify these lipid changes. Nicotine exposure had no effect on fatty acid amide hydrolase activity in the VTA, suggesting that changes in AEA and OEA signaling result from alterations in their nicotine-induced biosynthesis. Both CB(1) (by AEA and 2-AG) and non-CB(1) (by OEA) targets can alter the excitability and activity of the dopaminergic neurons in the VTA. Collectively, these findings implicate disrupted lipid signaling in the motivational effects of nicotine.

  16. [Effects of glycerol on the spectral properties of sodium caseinate].

    PubMed

    Li, Yan; Chang, Fen-fen; Gao, Huan-yuan; Cao, Qing; Jin, Li-e

    2015-01-01

    Although the immigration of water molecule, and diffusion and traversing of oxygen can be prevented by the edible film prepared through sodium caseinate, which plays a good protection role for the food, the strong hydrophilicity makes its watertightness and mechanical properties become inferior. Because the toughness and water resistance of SC films can be enhanced by glycerol (G) as an additive, it is necessary to elucidate the interaction between G and SC through the spectral characteristics such as fluorescence spectra, infrared spectra and UV spectra. The results show that the fluorescence intensity of SC decreases due to the addition of G. The binding constant obtained by the double logarithmic regression curve analysis is 1. 127 x 10(3) L . mol-1 and the number of binding sites reaches 1. 161. It indicates that the weak chemical bond is primary between G and SC molecules; From IR the absorption peaks of SC are almost the same before and after adding G. However, there is a certain difference among their absorption intensities. It reveals that the secondary structure of SC is affected, β folding length decreases, α helix, random coil structure, β angle structure increases, and the intermolecular hydrogen bond is strengthened; From UV the peptide bond structure of SC is not changed after the addition of G, but the polymer with larger molecular weight, which is formed by non-covalent bond, makes the peak intensity decrease. The research gives the mode of G and SC from the molecular level.

  17. Acoustic properties in glycerol glass-former: Molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Busselez, Remi; Pezeril, Thomas; Institut des Materiaux et Molecules du Mans Team

    2013-03-01

    Study of high-frequency collective dynamics around TeraHertz region in glass former has been a subject of intense investigations and debates over the past decade. In particular, the presence of the Boson peak characteristic of glassy material and its relation to other glass anomalies. Recently, experiments and simulations have underlined possible relation between Boson peak and transverse acoustic modes in glassy materials. In particular, simulations of simple Lennard Jones glass former have shown a relation between Ioffe-Regel criterion in transverse modes and Boson peak. We present here molecular dynamics simulation on high frequency dynamics of glycerol. In order to study mesoscopic order (0.5-5nm-1), we made use of large simulation box containing 80000 atoms. Analysis of collective longitudinal and transverse acoustic modes shows striking similarities in comparison with simulation of Lennard-Jones particles. In particular, it seems that a connection may exist between Ioffe-Regel criterion for transverse modes and Bose Peak frequency. However,in our case we show that this connection may be related with structural correlation arising from molecular clusters.

  18. The citric acid production from raw glycerol by Yarrowia lipolytica yeast and its regulation.

    PubMed

    Morgunov, Igor G; Kamzolova, Svetlana V; Lunina, Julia N

    2013-08-01

    The optimal cultivation conditions ensuring the maximal rate of citric acid (CA) biosynthesis by glycerol-grown mutant Yarrowia lipolytica NG40/UV7 were found to be as follows: growth limitation by inorganic nutrients (nitrogen, phosphorus, or sulfur), 28 °C, pH 5.0, dissolved oxygen concentration (pO₂) of 50 % (of air saturation), and pulsed addition of glycerol from 20 to 80 g L⁻¹ depending on the rate of medium titration. Under optimal conditions of fed-batch cultivation, in the medium with pure glycerol, strain Y. lipolytica NG40/UV7 produced 115 g L⁻¹ of CA with the mass yield coefficient of 0.64 g g⁻¹ and isocitric acid (ICA) amounted to 4.6 g L⁻¹; in the medium with raw glycerol, CA production was 112 g L⁻¹ with the mass yield coefficient of 0.90 g g⁻¹ and ICA amounted to 5.3 g L⁻¹. Based on the activities of enzymes involved in the initial stages of raw glycerol assimilation, the tricarboxylic acid cycle and the glyoxylate cycle, the mechanism of increased CA yield from glycerol-containing substrates in Y. lipolytica yeast was explained.

  19. Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

    PubMed

    Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M; Verstrepen, Kevin J

    2015-01-01

    Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

  20. Production of biohydrogen from crude glycerol in an upflow column bioreactor.

    PubMed

    Dounavis, Athanasios S; Ntaikou, Ioanna; Lyberatos, Gerasimos

    2015-12-01

    A continuous attached growth process for the production of biohydrogen from crude glycerol was developed. The process consisted of an anaerobic up-flow column bioreactor (UFCB), packed with cylindrical ceramic beads, which constituted the support matrix for the attachment of bacterial cells. The effect of crude glycerol concentration, pH and hydraulic retention time on glycerol conversion, hydrogen yield and metabolite distribution was investigated. It was shown that the most critical parameter for the efficient bioconversion was the pH of the influent, whereas the hydrogen yield increased with an increase in feed glycerol concentration and a decrease in the hydraulic retention time. The main soluble metabolite detected was 1,3-propanediol in all cases, followed by butyric and hexanoic acids. The latter is reported to be produced from glycerol for the first time. Acidification of the waste reached 38.5%, and the maximum H2 productivity was 107.3 ± 0.7 L/kg waste glycerol at optimal conditions.

  1. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces.

    PubMed

    Schrader, Alex M; Cheng, Chi-Yuan; Israelachvili, Jacob N; Han, Songi

    2016-07-28

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity.

  2. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces

    NASA Astrophysics Data System (ADS)

    Schrader, Alex M.; Cheng, Chi-Yuan; Israelachvili, Jacob N.; Han, Songi

    2016-07-01

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity.

  3. Glycerol assimilation and production of 1,3-propanediol by Citrobacter amalonaticus Y19.

    PubMed

    Ainala, Satish Kumar; Ashok, Somasundar; Ko, Yeounjoo; Park, Sunghoon

    2013-06-01

    Citrobacter amalonaticus Y19 (Y19) was isolated because of its ability for carbon monoxide-dependent hydrogen production (water-gas shift reaction). This paper reports the assimilation of glycerol and the production of 1,3-propanediol (1,3-PDO) by Y19. Genome sequencing revealed that Y19 contained the genes for the utilization of glycerol and 1,2-propanediol (pdu operon) along with those for the synthesis of coenzyme B12 (cob operon). On the other hand, it did not possess the genes for the fermentative metabolism of glycerol of Klebsiella pneumoniae, which consists of both the oxidative (dhaD and dhaK) and reductive (dhaB and dhaT) pathways. In shake-flask cultivation under aerobic conditions, Y19 could grow well with glycerol as the sole carbon source and produced 1,3-PDO. The level of 1,3-PDO production was improved when vitamin B12 was added to the culture medium under aerobic conditions. Under anaerobic conditions, cell growth and 1,3-PDO production on glycerol was also possible, but only when an exogenous electron acceptor, such as nitrate or fumarate, was added. This is the first report of the glycerol metabolism and 1,3-PDO production by C. amalonaticus Y19.

  4. Microbial utilization of crude glycerol for the production of value-added products.

    PubMed

    Dobson, Rosemary; Gray, Vincent; Rumbold, Karl

    2012-02-01

    Energy fuels for transportation and electricity generation are mainly derived from finite and declining reserves of fossil hydrocarbons. Fossil hydrocarbons are also used to produce a wide range of organic carbon-based chemical products. The current global dependency on fossil hydrocarbons will not be environmentally or economically sustainable in the long term. Given the future pessimistic prospects regarding the complete dependency on fossil fuels, political and economic incentives to develop carbon neutral and sustainable alternatives to fossil fuels have been increasing throughout the world. For example, interest in biodiesel has undergone a revival in recent times. However, the disposal of crude glycerol contaminated with methanol, salts, and free fatty acids as a by-product of biodiesel production presents an environmental and economic challenge. Although pure glycerol can be utilized in the cosmetics, tobacco, pharmaceutical, and food industries (among others), the industrial purification of crude glycerol is not economically viable. However, crude glycerol could be used as an organic carbon substrate for the production of high-value chemicals such as 1,3-propanediol, organic acids, or polyols. Microorganisms have been employed to produce such high-value chemicals and the objective of this article is to provide an overview of studies on the utilization of crude glycerol by microorganisms for the production of economically valuable products. Glycerol as a by-product of biodiesel production could be used a feedstock for the manufacture of many products that are currently produced by the petroleum-based chemical industry.

  5. Alternative Glycerol Balance Strategies among Saccharomyces Species in Response to Winemaking Stress

    PubMed Central

    Pérez-Torrado, Roberto; Oliveira, Bruno M.; Zemančíková, Jana; Sychrová, Hana; Querol, Amparo

    2016-01-01

    Production and balance of glycerol is essential for the survival of yeast cells in certain stressful conditions as hyperosmotic or cold shock that occur during industrial processes as winemaking. These stress responses are well-known in S. cerevisiae, however, little is known in other phylogenetically close related Saccharomyces species associated with natural or fermentation environments such as S. uvarum, S. paradoxus or S. kudriavzevii. In this work we have investigated the expression of four genes (GPD1, GPD2, STL1, and FPS1) crucial in the glycerol pool balance in the four species with a biotechnological potential (S. cerevisiae; S. paradoxus; S. uvarum; and S. kudriavzevii), and the ability of strains to grow under osmotic and cold stresses. The results show different pattern and level of expression among the different species, especially for STL1. We also studied the function of Stl1 glycerol symporter in the survival to osmotic changes and cell growth capacity in winemaking environments. These experiments also revealed a different functionality of the glycerol transporters among the different species studied. All these data point to different strategies to handle glycerol accumulation in response to winemaking stresses as hyperosmotic or cold-hyperosmotic stress in the different species, with variable emphasis in the production, influx, or efflux of glycerol. PMID:27064588

  6. Consolidating biofuel platforms through the fermentative bioconversion of crude glycerol to butanol.

    PubMed

    Johnson, Erin; Sarchami, Tahereh; Kießlich, Sascha; Munch, Garret; Rehmann, Lars

    2016-06-01

    Economic realities for the rising industrial biofuel production have changed substantially during the low oil price period starting in the mid 2010's. Increased competition requires the sector to increase productivity through the reduction of low-value by-products and full utilization of all value and energy stored in their respective feedstock. Biodiesel is produced commercially from substrates such as animal fat and vegetable oil, generating approximately 10 wt% crude glycerol as its main, currently underutilized, by-product. This crude glycerol is contaminated with catalyst, soap, free fatty acids, glycerides and methyl esters; hence only a small fraction enters the existing glycerol markets, while the purification costs for the majority of crude glycerol are simply too high. However, this presents a unique opportunity to generate additional value. One technical possibility is to use crude glycerol as a carbon source for butanol production, a compound of higher value and energy, a potential additive for gasoline and diesel fuels and bulk chemical commodity. Conversion facilities could be co-located with biodiesel plants, utilizing established infrastructure and adding significant value and productivity to the existing biodiesel industry. This review focuses on the current activities geared towards the bioconversion of crude glycerol to butanol.

  7. Biodiesel biorefinery: opportunities and challenges for microbial production of fuels and chemicals from glycerol waste.

    PubMed

    Almeida, João R M; Fávaro, Léia C L; Quirino, Betania F

    2012-07-18

    The considerable increase in biodiesel production worldwide in the last 5 years resulted in a stoichiometric increased coproduction of crude glycerol. As an excess of crude glycerol has been produced, its value on market was reduced and it is becoming a "waste-stream" instead of a valuable "coproduct". The development of biorefineries, i.e. production of chemicals and power integrated with conversion processes of biomass into biofuels, has been singled out as a way to achieve economically viable production chains, valorize residues and coproducts, and reduce industrial waste disposal. In this sense, several alternatives aimed at the use of crude glycerol to produce fuels and chemicals by microbial fermentation have been evaluated. This review summarizes different strategies employed to produce biofuels and chemicals (1,3-propanediol, 2,3-butanediol, ethanol, n-butanol, organic acids, polyols and others) by microbial fermentation of glycerol. Initially, the industrial use of each chemical is briefly presented; then we systematically summarize and discuss the different strategies to produce each chemical, including selection and genetic engineering of producers, and optimization of process conditions to improve yield and productivity. Finally, the impact of the developments obtained until now are placed in perspective and opportunities and challenges for using crude glycerol to the development of biodiesel-based biorefineries are considered. In conclusion, the microbial fermentation of glycerol represents a remarkable alternative to add value to the biodiesel production chain helping the development of biorefineries, which will allow this biofuel to be more competitive.

  8. Metabolic fluxes in Schizosaccharomyces pombe grown on glucose and mixtures of glycerol and acetate.

    PubMed

    Klein, Tobias; Heinzle, Elmar; Schneider, Konstantin

    2013-06-01

    Growth on glycerol has already been a topic of research for several yeast species, and recent publications deal with the regulatory mechanisms of glycerol assimilation by the fission yeast Schizosaccharomyces pombe. We investigated glycerol metabolism of S. pombe from a physiological point of view, characterizing growth and metabolism on a mixture of glycerol and acetate and comparing it to growth on glucose under respirative growth conditions in chemostat experiments. On glycerol/acetate mixtures, the cells grew with a maximum specific growth rate of 0.11 h(-1) where 46 % of the carbon was channeled into biomass and the key fermentation product ethanol was not detectable. (13)C-assisted metabolic flux analysis resolved substrate distributions through central carbon metabolism, proving that glycerol is used as a precursor for glycolysis, gluconeogenesis, and the pentose phosphate pathway, while acetate enters the tricarboxylic acid cycle via acetyl-CoA. Considering compartmentalization between cytosol and mitochondria in the metabolic model, we found compartmentalization of biosynthesis for the amino acids aspartate and leucine. Balancing of redox cofactors revealed an abundant production of cytosolic NADPH that must be finally regenerated via the respiratory chain shown by the simulated and measured CO2 production and oxygen consumption rates which were in good agreement.

  9. Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp.

    PubMed

    Maru, Biniam T; Constanti, Magda; Stchigel, Alberto M; Medina, Francesc; Sueiras, Jesus E

    2013-01-01

    Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1). It was found that, when an initial concentration of 20 g/L of glycerol was used, all three strains and their mixture produced substantial amounts of hydrogen ranging from 2400 to 3500 mL/L, being highest for C. freundii H3 (3547 mL/L) and Enterobacter spH1 (3506 mL/L). The main nongaseous fermentation products were ethanol and acetate, albeit in different ratios. For Enterobacter spH1, Enterobacter spH2, C. freundii H3, and the mixture (1:1:1), the ethanol yields (in mol EtOH/mol glycerol consumed) were 0.96, 0.67, 0.31, and 0.66, respectively. Compared to the individual strains, the mixture (1:1:1) did not show a significantly higher hydrogen level, indicating that there was no synergistic effect. Enterobacter spH1 was selected for further investigation because of its higher yield of hydrogen and ethanol.

  10. High-purity propionate production from glycerol in mixed culture fermentation.

    PubMed

    Chen, Yun; Wang, Ting; Shen, Nan; Zhang, Fang; Zeng, Raymond J

    2016-11-01

    High-purity propionate production from glycerol in mixed culture fermentation (MCF) induced by high ammonium concentration was investigated. Fed-batch experiments revealed that higher ammonium concentration (>2.9g/L) had simultaneous negative effects on acetate and propionate degradation. Propionate production and yield was up to 22.6g/L and 0.45g COD/g COD glycerol, respectively, with a purity of 96%. Sequential batch experiments demonstrated that the yields of propionate were 0.3±0.05, 0.32±0.01, and 0.34±0.03g COD/g COD at a glycerol concentration of 2.78, 4.38, and 5.56g/L, respectively, and the purity of propionate was 91-100%. Microbial community analysis showed that the phylum Firmicutes dominated the bacterial community at different glycerol concentrations. However, the Methanosaeta population decreased from 46% to 6% when glycerol concentration increased from 2.78 to 5.56g/L, resulting in lower acetate degradation rate. Thus, the present study might provide an alternative option for the production of propionate from glycerol via MCF.

  11. Fermentation of residual glycerol by Clostridium acetobutylicum ATCC 824 in pure and mixed cultures.

    PubMed

    Dams, Rosemeri I; Guilherme, Alexandre A; Vale, Maria S; Nunes, Vanja F; Leitão, Renato C; Santaella, Sandra T

    2016-12-01

    The aim of this research was to estimate the production of hydrogen, organic acids and alcohols by the strain of Clostridium acetobutylicum ATCC 824 using residual glycerol as a carbon source. The experiments were carried out in pure and mixed cultures in batch experiments. Three different sources of inocula for mixed culture were used. Ruminal liquid from goats and sludge collected from two upflow anaerobic sludge blanket reactors treating municipal wastewater and brewery effluent were tested for hydrogen, organic acids and alcohols production with or without C. acetobutylicum ATCC 824. The main detected end-products from the glycerol fermentation were hydrogen, organic acids (acetic, propionic, butyric and caproic) and alcohol (ethanol and 1,3-propanediol - 1,3PD). High hydrogen (0.44 mol H2/mol glycerol consumed) and 1,3PD (0.32 mol 1,3PD/mol glycerol consumed) yields were obtained when the strain C. acetobutylicum ATCC 824 was bioaugmented into the sludge from municipal wastewater using 5 g/L of glycerol. Significant concentrations of n-caproic acid were detected in the ruminal liquid when amended with C. acetobutylicum ATCC 824. The results suggest that glycerol can be used for the generation of H2, 1,3PD and n-caproic acid using C. acetobutylicum ATCC 824 as agent in pure or mixed cultures.

  12. Effects of glycerol on apoptotic signaling pathways during boar spermatozoa cryopreservation.

    PubMed

    Zeng, Changjun; Tang, Keyi; He, Lian; Peng, Wenpei; Ding, Li; Fang, Donghui; Zhang, Yan

    2014-06-01

    Artificial insemination (AI) with post-thawed boar spermatozoa results in low farrowing rates and reduced litter sizes mainly due to cryoinjury or damages to spermatozoa during cryopreservation. Low viability and motility of post-thawed boar spermatozoa are highly associated with apoptosis during cryopreservation. Although glycerol is widely used a cryoprotectant (CPA) for boar spermatozoa cryopreservation, the mechanism and relationship between glycerol and apoptosis-related gene expression needs to be clarified. In this study, we treated boar spermatozoa with different concentrations of glycerol in lactose egg yolk (LEY) extender to evaluate the apoptosis-related gene expression and protease activities of caspases. These results show that: (1) low concentrations of glycerol (2% and 3%) were more suitable for boar spermatozoa cryopreservation; (2) apoptosis-related genes involved in intrinsic mitochondrial and extrinsic death receptor apoptotic signaling pathways were widely expressed in different concentrations of glycerol treated boar spermatozoa; (3) there was a significant positive correlation (r=0.840, P=0.037) between the percentage of Annexin V(+)/PI(+) staining spermatozoa and caspase-6/9 protease activity. In conclusion, 2% and 3% glycerol have the best anti-apoptotic effects, and the expression of Fas/FasL and Bcl-2/Bax have a strong correlation with spermatozoa parameters.

  13. Biotransformation of glycerol to dihydroxyacetone by recombinant Gluconobacter oxydans DSM 2343.

    PubMed

    Gätgens, Cornelia; Degner, Ursula; Bringer-Meyer, Stephanie; Herrmann, Ute

    2007-09-01

    The genus Gluconobacter is well known for its rapid and incomplete oxidation of a wide range of substrates. Therefore, Gluconobacter oxydans especially is used for several biotechnological applications, e.g., the efficient oxidation of glycerol to dihydroxyacetone (DHA). For this reaction, G. oxydans is equipped with a membrane-bound glycerol dehydrogenase that is also described to oxidize sorbitol, gluconate, and arabitol. Here, we demonstrated the impact of sldAB overexpression on glycerol oxidation: Beside a beneficial effect on the transcript level of the sldB gene, the growth on glycerol as a carbon source was significantly improved in the overexpression strains (OD 2.8 to 2.9) compared to the control strains (OD 2.8 to 2.9). Furthermore, the DHA formation rate, as well as the final DHA concentration, was affected so that up to 350 mM of DHA was accumulated by the overexpression strains when 550 mM glycerol was supplied (control strain: 200 to 280 mM DHA). Finally, we investigated the effect on sldAB overexpression on the G. oxydans transcriptome and identified two genes involved in glycerol metabolism, as well as a regulator of the LysR family.

  14. Role of CgHOG1 in Stress Responses and Glycerol Overproduction of Candida glycerinogenes.

    PubMed

    Ji, Hao; Zhuge, Bin; Zong, Hong; Lu, Xinyao; Fang, Huiying; Zhuge, Jian

    2016-12-01

    Candida glycerinogenes, the glycerol producer with excellent multi-stress tolerances, is considered to be a potential biotechnological host used in the production of glycerol and its derivatives under extreme fermentation conditions. In this study, to evaluate the multiple roles of mitogen-activated protein kinase CgHOG1, we constructed a gene disruption system in the diploid C. glycerinogenes to obtain CgHOG1 null mutant. Pseudohyphae generation of the CgHOG1 mutant under non-inducing condition indicated a repressor role in morphological transitions. Disruption of CgHOG1 resulted in increased sensitivities to osmotic, acetic acid, and oxidative stress but not involved in thermotolerance. In the CgHOG1 mutant, NaCl shock failed to stimulate the accumulation of intracellular glycerol and was fatal. In addition, the CgHOG1 mutant displayed a significant prolonged growth lag phase in YPD medium with no decrease in glycerol production, whereas the mutant cannot grow under hyperosmotic condition with no detectable glycerol in broth. These results suggested that CgHOG1 plays important roles in morphogenesis and multi-stress tolerance. The growth and glycerol overproduction under osmotic stress are heavily dependent on CgHOG1 kinase.

  15. Metabolic engineering of Escherichia coli for efficient free fatty acid production from glycerol.

    PubMed

    Wu, Hui; Karanjikar, Mukund; San, Ka-Yiu

    2014-09-01

    Crude glycerol, generated as waste by-product in biodiesel production process, has been considered as an important carbon source for converting to value-added bioproducts recently. Free fatty acids (FFAs) can be used as precursors for the production of biofuels or biochemicals. Microbial biosynthesis of FFAs can be achieved by introducing an acyl-acyl carrier protein thioesterase into Escherichia coli. In this study, the effect of metabolic manipulation of FFAs synthesis cycle, host genetic background and cofactor engineering on FFAs production using glycerol as feed stocks was investigated. The highest concentration of FFAs produced by the engineered stain reached 4.82g/L with the yield of 29.55% (g FFAs/g glycerol), about 83% of the maximum theoretical pathway value by the type II fatty acid synthesis pathway. In addition, crude glycerol from biodiesel plant was also used as feedstock in this study. The FFA production was 3.53g/L with a yield of 24.13%. The yield dropped slightly when crude glycerol was used as a carbon source instead of pure glycerol, while it still can reach about 68% of the maximum theoretical pathway yield.

  16. Improvement of Sporobolomyces ruberrimus carotenoids production by the use of raw glycerol.

    PubMed

    Cardoso, L A C; Jäckel, S; Karp, S G; Framboisier, X; Chevalot, I; Marc, I

    2016-01-01

    The red yeast Sporobolomyces ruberrimus H110 was able to use glycerol as a carbon source. The highest concentration (0.51gL(-1)) and productivity (0.0064gL(-1)h(-1)) of carotenoids were achieved when raw glycerol from biodiesel production, containing around 1gL(-1) of fatty acids, was used as the carbon source, which represented increases of 27% and 1.5×, respectively, in relation to pure glycerol. Mass spectrometry analysis led to the identification of four carotenoids in the fermented samples, torularhodin, torulene, β-carotene and γ-carotene. The use of raw glycerol also enhanced the proportion of torularhodin (69% against 59% in pure glycerol). The addition of individual fatty acids (palmitic, stearic, oleic and linoleic acids) to pure glycerol resulted in increases between 15% and 25% in maximum concentration and between 1.6× and 2.0× in productivity of carotenoids. The presence of palmitic and oleic acids increased the torularhodin proportion to 66%.

  17. Pyrolysis of glycerol for the production of hydrogen or syn gas.

    PubMed

    Valliyappan, T; Bakhshi, N N; Dalai, A K

    2008-07-01

    Biodiesel has high potential as alternative liquid transportation fuel because it is renewable and CO(2) neutral, and has similar properties as diesel fuel. Glycerol is a by-product obtained during the production of biodiesel. Canadian government has planned to produce 500 million litres of biodiesel by 2010. An increase in biodiesel production would decrease the market price of glycerol. The objective of this study is to pyrolyse glycerol for the production of clean fuels such as H(2) or a feedstock such as syn gas for additional transportation fuel via Fisher-Tropsch synthesis. The pyrolysis of glycerol was carried out at various flow rates of N(2) (30-70 mL/min), temperatures (650-800 degrees C) and types and sizes of packing material in a tubular reactor at atmospheric pressure. The products were mostly gas, essentially consisting of CO, H(2), CO(2), CH(4) and C(2)H(4). It was observed that temperature, carrier flow rates and particle diameter of packing material had profound effects on the conversion of glycerol as well as product distribution. Composition of product gas ranged between syn gas 70-93 mol%, CH(4) 3-15 mol% and C(2)H(4) 2-12 mol% and heating value ranged from 13 to 22 MJ/m(3). This study indicates that the bio-glycerol has potential in making syn gas and medium heating value gases.

  18. Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs) in U.S. Great Basin hot springs.

    PubMed

    Hedlund, Brian P; Paraiso, Julienne J; Williams, Amanda J; Huang, Qiuyuan; Wei, Yuli; Dijkstra, Paul; Hungate, Bruce A; Dong, Hailiang; Zhang, Chuanlun L

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are membrane-spanning lipids that likely stabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs are known to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S. Great Basin (temperature: 31-95°C; pH: 6.8-10.7). bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal). The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration of bGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS(-)) and positively with properties of oxygenated, low temperature sites (O2, NO(-) 3). Two-way cluster analysis and nonmetric multidimensional scaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (≤70°C).

  19. In situ produced branched glycerol dialkyl glycerol tetraethers in suspended particulate matter from the Yenisei River, Eastern Siberia

    NASA Astrophysics Data System (ADS)

    De Jonge, Cindy; Stadnitskaia, Alina; Hopmans, Ellen C.; Cherkashov, Georgy; Fedotov, Andrey; Sinninghe Damsté, Jaap S.

    2014-01-01

    Soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs) in marine river fan sediments have a potential use for determining changes in the mean annual temperature (MAT) and pH of the river watershed soils. Prior to their incorporation in marine sediments, the compounds are transported to the marine system by rivers. However, emerging evidence suggests that the brGDGTs in freshwater systems can be derived from both soil run-off and in situ production. The production of brGDGTs in the river system can complicate the interpretation of the brGDGT signal delivered to the marine system. Therefore, we studied the distribution of brGDGT lipids in suspended particulate matter (SPM) of the Yenisei River. Chromatographic improvements allowed quantification of the recently described hexamethylated brGDGT isomer, characterized by having two methyl groups at the 6/6‧ instead of the 5/5‧ positions, in an environmental dataset for the first time. This novel compound was the most abundant brGDGT in SPM from the Yenisei. Its fractional abundance correlated well with that of the 6-methyl isomer of the hexamethylated brGDGT that contains one cyclopentane moiety. The Yenisei River watershed is characterized by large differences in MAT (>11 °C) as it spans a large latitudinal range (46-73°N), which would be expected to be reflected in brGDGT distributions of its soils. However, the brGDGT distributions in its SPM show little variation. Furthermore, the reconstructed pH values are high compared to the watershed soil pH. We, therefore, hypothesize that the brGDGTs in the Yenisei River SPM are predominantly produced in situ and not primarily derived from erosion of soil. This accounts for the absence of a change in the temperature signal, as the river water temperature is more stable. Using a lake calibration, the reconstructed temperature values agree with the mean summer temperatures (MST) recorded. The brGDGTs delivered to the sea by the Yenisei River during this

  20. Synthesis of Bifunctional Fe3O4@SiO2-Ag Magnetic-Plasmonic Nanoparticles by an Ultrasound Assisted Chemical Method

    NASA Astrophysics Data System (ADS)

    Chu, Dung Tien; Sai, Doanh Cong; Luu, Quynh Manh; Tran, Hong Thi; Quach, Truong Duy; Kim, Dong Hyun; Nguyen, Nam Hoang

    2017-03-01

    Bifunctional magnetic-plasmonic nanoparticles (NPs)—Fe3O4@SiO2-Ag were successfully synthesized by an ultrasound assisted chemical method. Silver ions were absorbed and then reduced by sodium borohydride on the surface of 3-aminopropyltriethoxysilane (APTES) functionalized silica-coated magnetic NPs, then they were reduced under the influence of a 200 W ultrasonic wave for 60 min. When the amount of precursor silver ions increased, the relative intensity of diffraction peaks of silver crystals in all samples increased with the atomic ratio of silver/iron increasing from 0.208 to 0.455 and saturation magnetization (M s) decreasing from 44.68 emu/g to 34.74 emu/g. The NPs have superparamagnetic properties and strong surface plasmon absorption at 420 nm, which make these particles promising for biomedical applications.

  1. Decoupling optical and electronic optimization of organic solar cells using high-performance temperature-stable TiO{sub 2}/Ag/TiO{sub 2} electrodes

    SciTech Connect

    Kim, Kwang-Dae; Pfadler, Thomas; Zimmermann, Eugen; Feng, Yuyi; Weickert, Jonas Schmidt-Mende, Lukas; Dorman, James A.

    2015-10-01

    An electrode structured with a TiO{sub 2}/Ag/TiO{sub 2} (TAT) multilayer as indium tin oxide (ITO) replacement with a superior thermal stability has been successfully fabricated. This electrode allows to directly tune the optical cavity mode towards maximized photocurrent generation by varying the thickness of the layers in the sandwich structure. This enables tailored optimization of the transparent electrode for different organic thin film photovoltaics without alteration of their electro-optical properties. Organic photovoltaic featuring our TAT multilayer shows an improvement of ∼12% over the ITO reference and allows power conversion efficiencies (PCEs) up to 8.7% in PTB7:PC{sub 71}BM devices.

  2. Thermodynamic investigation of the charge-ordered insulating state of the quasi-one-dimensional organic system (DI-DCNQI)2Ag.

    PubMed

    Nakazawa, Yasuhiro; Seki, Mitsuro; Saito, Kazuya; Hiraki, Ko-ichi; Takahashi, Toshihiro; Kanoda, Kazushi; Sorai, Michio

    2002-02-18

    Heat capacity measurements of a charge-ordered organic conductor (DI-DCNQI)2Ag have been performed in a temperature range between 0.3 and 14 K. We found no thermal anomaly at the Néel temperature ( T(N) = 5.5 K) but instead a T-linear term suggestive of the spin excitations of one-dimensional character in the charge-ordered insulating state. The analysis of the T-linear term and the excess entropy indicates that the charge fluctuations in the charge-ordered state influence the growth of spin excitations at elevated temperatures, which seems to be a peculiar aspect of a 1D charge-ordered system.

  3. Mechanism enabling the observation of the formally optically-forbidden 2Ag- and 1Bu- states in resonance-Raman excitation profiles of spheroidene in KBr disc

    NASA Astrophysics Data System (ADS)

    Nagae, Hiroyoshi; Koyama, Yasushi

    2010-07-01

    An expression for the Albrecht A-term resonance-Raman excitation profiles (RREP) of a pigment dispersed in a KBr disc, in such a way that the pigment molecules aggregate in a microcrystal and the microcrystals are dispersed in the KBr disc, is formulated by taking into account the self-absorption of incident and scattered light and the distribution of microcrystals properly. Based on the resultant formula, simulations for the RREPs of spheroidene dispersed in KBr disc were carried out in the spectral region from 12,000 to 24,000 cm -1. Fairly good agreement between the simulations and the observed RREPs was obtained for different concentrations of spheroidene. Mechanisms have been investigated which enable the observation of the formally optically-forbidden (very weakly allowed) 2Ag- and 1Bu- states of spheroidne in RREPs free from the contribution of the optically-allowed 1Bu+ state, and a two-step self-absorption mechanism is proposed.

  4. Improved electron transfer and plasmonic effect in dye-sensitized solar cells with bi-functional Nb-doped TiO2/Ag ternary nanostructures

    NASA Astrophysics Data System (ADS)

    Park, Jung Tae; Chi, Won Seok; Jeon, Harim; Kim, Jong Hak

    2014-02-01

    TiO2 nanoparticles are surface-modified via atom transfer radical polymerization (ATRP) with a hydrophilic poly(oxyethylene)methacrylate (POEM), which can coordinate to the Ag precursor, i.e. silver trifluoromethanesulfonate (AgCF3SO3). Following the reduction of Ag ions, a Nb2O5 doping process and calcination at 450 °C, bi-functional Nb-doped TiO2/Ag ternary nanostructures are generated. The resulting nanostructures are characterized by energy-filtering transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy. The dye-sensitized solar cell (DSSC) based on the Nb-doped TiO2/Ag nanostructure photoanode with a polymerized ionic liquid (PIL) as the solid polymer electrolyte shows an overall energy conversion efficiency (η) of 6.9%, which is much higher than those of neat TiO2 (4.7%) and Nb-doped TiO2 (5.4%). The enhancement of η is mostly due to the increase of current density, attributed to the improved electron transfer properties including electron injection, collection, and plasmonic effects without the negative effects of charge recombination or problems with corrosion. These properties are supported by intensity modulated photocurrent/voltage spectroscopy (IMPS/IMVS) and incident photon-to-electron conversion efficiency (IPCE) measurements.TiO2 nanoparticles are surface-modified via atom transfer radical polymerization (ATRP) with a hydrophilic poly(oxyethylene)methacrylate (POEM), which can coordinate to the Ag precursor, i.e. silver trifluoromethanesulfonate (AgCF3SO3). Following the reduction of Ag ions, a Nb2O5 doping process and calcination at 450 °C, bi-functional Nb-doped TiO2/Ag ternary nanostructures are generated. The resulting nanostructures are characterized by energy-filtering transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy. The dye-sensitized solar cell (DSSC) based on the Nb

  5. Anion effects on electronic structure and electrodynamic properties of the Mott insulator κ -(BEDT-TTF ) 2Ag2(CN) 3

    NASA Astrophysics Data System (ADS)

    Pinterić, M.; Lazić, P.; Pustogow, A.; Ivek, T.; Kuveždić, M.; Milat, O.; Gumhalter, B.; Basletić, M.; Čulo, M.; Korin-Hamzić, B.; Löhle, A.; Hübner, R.; Sanz Alonso, M.; Hiramatsu, T.; Yoshida, Y.; Saito, G.; Dressel, M.; Tomić, S.

    2016-10-01

    The Mott insulator κ -(BEDT-TTF ) 2Ag2(CN) 3 forms a highly-frustrated triangular lattice of S =1 /2 dimers with a possible quantum-spin-liquid state. Our experimental and numerical studies reveal the emergence of a slight charge imbalance between crystallographically inequivalent sites, relaxor dielectric response, and hopping dc transport. In a broader perspective we conclude that the universal properties of strongly-correlated charge-transfer salts with spin liquid state are an anion-supported valence band and cyanide-induced quasidegenerate electronic configurations in the relaxed state. The generic low-energy excitations are caused by charged domain walls rather than by fluctuating electric dipoles. They give rise to glassy dynamics characteristic of dimerized Mott insulators, including the sibling compound κ -(BEDT-TTF)2Cu2 (CN )3.

  6. Roles of sugar alcohols in osmotic stress adaptation. Replacement of glycerol by mannitol and sorbitol in yeast

    SciTech Connect

    Shen, B.; Hohmann, S.; Jensen, R.G.; Bohnert, H.J.

    1999-09-01

    For many organisms there is a correlation between increases of metabolites and osmotic stress tolerance, but the mechanisms that cause this protection are not clear. To understand the role of polyols, genes for bacterial mannitol-1-P dehydrogenase and apply sorbitol-6-P dehydrogenase were introduced into a Saccharomyces cerevisiae mutant deficient in glycerol synthesis. Sorbitol and mannitol provided some protection, but less than that generated by a similar concentration of glycerol generated by glycerol-3-P dehydrogenase (GPD1). Reduced protection by polyols suggested that glycerol had specific functions for which mannitol and sorbitol could not substitute, and that the absolute amount of the accumulating osmoticum might not be crucial. The retention of glycerol and mannitol-sorbitol, respectively, was a major difference. During salt stress, cells retained more of the six-carbon polyois than glycerol. The authors suggest that the loss of {gt} 98% of the glycerol synthesized could provide a safety value that dissipates reducing power, which a similar high intracellular concentration of retained polyois would be less protective. To understand the role of glycerol in salt tolerance, salt-tolerant suppressor mutants were isolated from the glycerol-deficient strain. One mutant, sr13, partially suppressed the salt-sensitive phenotype of the glycerol-deficient line, probably due to a doubling of [K{sup +}] accumulating during stress. The authors compare these results to the osmotic adjustment concept typically applied to accumulating metabolites in plants. The accumulation of polyois may have dual functions: facilitating osmotic adjustment and supporting redox control.

  7. The effect of glycerol from biodiesel production waste as a plasticizer on physical character edible film of chitosan

    NASA Astrophysics Data System (ADS)

    Rosyid, Fajar Abdul; Triastuti, Rr. Juni; Andriyono, Sapto

    2017-02-01

    Chitosan edible film is a thin layer of clear packaging made from chitosan edible and biodegradable. Edible chitosan films are stiffer and less elastic, so it should be added plasticizer glycerol. One source of glycerol is inexpensive and easily obtained is crude glycerol from biodiesel production. The purpose of this study was to determine the effect of various concentrations of crude glycerol plasticizer on the physical characteristics of chitosan edible film and determine the best concentration of crude glycerol plasticizer. This study used a completely randomized design (CRD) with five treatments and four replications. The Edible film using the g chitosan and some plasticizers concentration of crude glycerol (0.2, 0.4, 0.8, and 1 mL) and a control treatment that used 0.4 mL of pure glycerol was made. The results showed that the use of crude glycerol plasticizer had effect to the physical character of chitosan edible film. Increasing concentrations of crude glycerol plasticizer exhibits the lowers value of the thickness and tensile strength, however, can increase the value of percent elongation. The best concentration of this research is the treatment of B (0.2 ml crude glycerol) which resulted in 0.55 mm thickness, the tensile strength of 95.38 kgf/cm2 and a percent elongation of 2.13%.

  8. The role of micronutrients and strategies for optimized continual glycerol production from carbon dioxide by Dunaliella tertiolecta.

    PubMed

    Chow, Yvonne; Tu, Wang Yung; Wang, David; Ng, Daphne H P; Lee, Yuan Kun

    2015-10-01

    The microalga Dunaliella tertiolecta synthesizes intracellular glycerol as an osmoticum to counteract external osmotic pressure in high saline environments. The species has recently been found to release and accumulate extracellular glycerol, making it a suitable candidate for sustainable industrial glycerol production if a sufficiently high product titre yield can be achieved. While macronutrients such as nitrogen and phosphorus are essential and well understood, this study seeks to understand the influence of the micronutrient profile on glycerol production. The effects of metallic elements calcium, magnesium, manganese, zinc, cobalt, copper, and iron, as well as boron, on glycerol production as well as cell growth were quantified. The relationship between cell density and glycerol productivity was also determined. Statistically, manganese recorded the highest improvement in glycerol production as well as cell growth. Further experiments showed that manganese availability was associated with higher superoxide dismutase formation, thus suggesting that glycerol production is negatively affected by oxidative stress and the manganese bound form of this enzyme is required in order to counteract reactive oxygen species in the cells. A minimum concentration of 8.25 × 10(-5)  g L(-1) manganese was sufficient to overcome this problem and achieve 10 g L(-1) extracellular glycerol, compared to 4 g L(-1) without the addition of manganese. Unlike cell growth, extracellular glycerol production was found to be negatively affected by the amount of calcium present in the normal growth medium, most likely due to the lower cell permeability at high calcium concentrations. The inhibitory effects of iron also affected extracellular glycerol production more significantly than cell growth and several antagonistic interaction effects between various micronutrients were observed. This study indicates how the optimization of these small amounts of nutrients in a two

  9. Dietary linoleic acid elevates the endocannabinoids 2-AG and anandamide and promotes weight gain in mice fed a low fat diet.

    PubMed

    Alvheim, Anita Røyneberg; Torstensen, Bente E; Lin, Yu Hong; Lillefosse, Haldis Haukås; Lock, Erik-Jan; Madsen, Lise; Frøyland, Livar; Hibbeln, Joseph R; Malde, Marian Kjellevold

    2014-01-01

    Dietary intake of linoleic acid (LNA, 18:2n-6) has increased dramatically during the 20th century and is associated with greater prevalence of obesity. The endocannabinoid system is involved in regulation of energy balance and a sustained hyperactivity of the endocannabinoid system may contribute to obesity. Arachidonic acid (ARA, 20:4n-6) is the precursor for 2-AG and anandamide (AEA), and we sought to determine if low fat diets (LFD) could be made obesogenic by increasing the endocannabinoid precursor pool of ARA, causing excessive endocannabinoid signaling leading to weight gain and a metabolic profile associated with obesity. Mice (C57BL/6j, 6 weeks of age) were fed 1 en% LNA and 8 en% LNA in low fat (12.5 en%) and medium fat diets (MFD, 35 en%) for 16 weeks. We found that increasing dietary LNA from 1 to 8 en% in LFD and MFD significantly increased ARA in phospholipids (ARA-PL), elevated 2-AG and AEA in liver, elevated plasma leptin, and resulted in larger adipocytes and more macrophage infiltration in adipose tissue. In LFD, dietary LNA of 8 en% increased feed efficiency and caused greater weight gain than in an isocaloric reduction to 1 en% LNA. Increasing dietary LNA from 1 to 8 en% elevates liver endocannabinoid levels and increases the risk of developing obesity. Thus a high dietary content of LNA (8 en%) increases the adipogenic properties of a low fat diet.

  10. Dynamic Mechanisms of the Bactericidal Action of an Al2O3-TiO2-Ag Granular Material on an Escherichia coli Strain.

    PubMed

    Tartanson, Marie-Anne; Soussan, Laurence; Rivallin, Matthieu; Pecastaings, Sophie; Chis, Cristian V; Penaranda, Diego; Roques, Christine; Faur, Catherine

    2015-10-01

    The bactericidal activity of an Al2O3-TiO2-Ag granular material against an Escherichia coli strain was confirmed by a culture-based method. In particular, 100% of microorganisms were permanently inactivated in 30 to 45 min. The present work aimed to investigate the mechanisms of the bactericidal action of this material and their dynamics on Escherichia coli using different techniques. Observations by transmission electron microscopy (TEM) at different times of disinfection revealed morphological changes in the bacteria as soon as they were put in contact with the material. Notably highlighted were cell membrane damage; cytoplasm detachment; formation of vacuoles, possibly due to DNA condensation, in association with regions exhibiting different levels of electron density; and membrane lysis. PCR and flow cytometry analyses were used to confirm and quantify the observations of cell integrity. The direct exposure of cells to silver, combined with the oxidative stress induced by the reactive oxygen species (ROS) generated, was identified to be responsible for these morphological alterations. From the first 5 min of treatment with the Al2O3-TiO2-Ag material, 98% of E. coli isolates were lysed. From 30 min, cell viability decreased to reach total inactivation, although approximately 1% of permeable E. coli cells and 1% of intact cells (10(5) genomic units·ml(-1)) were evidenced. This study demonstrates that the bactericidal effect of the material results from a synergic action of desorbed and supported silver. Supported silver was shown to generate the ROS evidenced.

  11. Glycerol Metabolism and PrfA Activity in Listeria monocytogenes▿ †

    PubMed Central

    Joseph, Biju; Mertins, Sonja; Stoll, Regina; Schär, Jennifer; Umesha, Kanasinakatte Rudrappa; Luo, Qin; Müller-Altrock, Stefanie; Goebel, Werner

    2008-01-01

    Listeria monocytogenes is able to efficiently utilize glycerol as a carbon source. In a defined minimal medium, the growth rate (during balanced growth) in the presence of glycerol is similar to that in the presence of glucose or cellobiose. Comparative transcriptome analyses of L. monocytogenes showed high-level transcriptional upregulation of the genes known to be involved in glycerol uptake and metabolism (glpFK and glpD) in the presence of glycerol (compared to that in the presence of glucose and/or cellobiose). Levels of expression of the genes encoding a second putative glycerol uptake facilitator (GlpF2) and a second putative glycerol kinase (GlpK2) were less enhanced under these conditions. GlpK1 but not GlpK2 was essential for glycerol catabolism in L. monocytogenes under extracellular conditions, while the loss of GlpK1 affected replication in Caco-2 cells less than did the loss of GlpK2 and GlpD. Additional genes whose transcription levels were higher in the presence of glycerol than in the presence of glucose and cellobiose included those for two dihydroxyacetone (Dha) kinases and many genes that are under carbon catabolite repression control. Transcriptional downregulation in the presence of glycerol (compared to those in the presence glucose and cellobiose) was observed for several genes and operons that are positively regulated by glucose, including genes involved in glycolysis, N metabolism, and the biosynthesis of branched-chain amino acids. The highest level of transcriptional upregulation was observed for all PrfA-dependent genes during early and late logarithmic growth in glycerol. Under these conditions, a low level of HPr-Ser-P and a high level of HPr-His-P were present in the cells, suggesting that all enzyme IIA (EIIA) (or EIIB) components of the phosphotransferase system (PTS) permeases expressed will be phosphorylated. These and other data suggest that the phosphorylation state of PTS permeases correlates with PrfA activity. PMID:18502850

  12. The effect of glycerol hyperhydration on olympic distance triathlon performance in high ambient temperatures.

    PubMed

    Coutts, Aaron; Reaburn, Peter; Mummery, Kerry; Holmes, Mark

    2002-03-01

    The purpose of this study was to examine the effect of prior glycerol loading on competitive Olympic distance triathlon performance (ODT) in high ambient temperatures. Ten (3 female and 7 male) well-trained triathletes (VO2max = 58.4 +/- 2.4ml kg(-1) min(-1); bestODTtime = 131.5 +/- 2.6 min) completed 2 ODTs (1.5-km swim, 40-km bicycle, 10-km run) in a randomly assigned (placebo/ glycerol) double-blind study conducted 2 weeks apart. The wet-bulb globe temperature (outdoors) was 30.5 +/- 0.5 degrees C (relative humidity: 46.3 +/- 1.1%; hot) and 25.4 +/- 0.2 degrees C (relative humidity: 51.7 +/- 2.4%; warm) for day 1 and day 2, respectively. The glycerol solution consisted of 1.2 g of glycerol per kilogram of body mass (BM) and 25 ml of a 0.75 g x kg(-1) BM carbohydrate solution (Gatorade) and was consumed over a 60-min period, 2 hours prior to each ODT. Measures of performance (ODT time), fluid retention, urine output, blood plasma volume changes, and sweat loss were obtained prior to and during the ODT in both the glycerol and placebo conditions. Following glycerol loading, the increase in ODT completion time between the hot and warm conditions was significantly less than the placebo group (placebo 11:40 min vs. glycerol 1:47 min; p < .05). The majority of the performance improvement occurred during the final 10-km run leg of ODT on the hot day. Hyperhydration occurred as a consequence of a reduced diuresis (p < .05) and a subsequent increase in fluid retention (p < .05). No significant differences were observed in sweat loss between the glycerol and placebo conditions. Plasma volume expansion during the loading period was significantly greater (p < .05) on the hot day when glycerol appeared to attenuate the performance decrement in the heat. The present results suggest that glycerol hyperhydration prior to ODT in high ambient temperatures may provide some protection against the negative performance effects of competing in the heat.

  13. Characterization of oleaginous yeasts accumulating high levels of lipid when cultivated in glycerol and their potential for lipid production from biodiesel-derived crude glycerol.

    PubMed

    Polburee, Pirapan; Yongmanitchai, Wichien; Lertwattanasakul, Noppon; Ohashi, Takao; Fujiyama, Kazuhito; Limtong, Savitree

    2015-12-01

    This study attempted to identify oleaginous yeasts and selected the strain that accumulated the largest quantity of lipid for lipid production from glycerol. Two-step screening of 387 yeast strains revealed 23 oleaginous strains that accumulated quantities of lipid higher than 20 % of their biomass when cultivated in glycerol. These strains were identified to be four ascomycetous yeast species i.e. Candida silvae, Kodamaea ohmeri, Meyerozyma caribbica, and Pichia manshurica, and five basidiomycetous yeast species i.e. Cryptococcus cf. podzolicus, Cryptococcus laurentii, Rhodosporidium fluviale, Rhodotorula taiwanensis, and Sporidiobolus ruineniae. Rhodosporidium fluviale DMKU-RK253 accumulated the highest quantity of lipid equal to 65.2 % of its biomass (3.9 g L(-1) lipid and 6.0 g L(-1) biomass) by shaking flask cultivation in crude glycerol. The main fatty acids in the accumulated lipid of this strain consisted of oleic acid, linoleic acid, and palmitic acid. Therefore, R. fluviale DMKU-RK253 has potential for producing lipid for biodiesel manufacturing using crude glycerol as a feedstock.

  14. Protective effect of sulfated chitosan of C3 sulfation on glycerol-induced acute renal failure in rat kidney.

    PubMed

    Xing, Ronge; Liu, Song; Yu, Huahua; Qin, Yukun; Chen, Xiaolin; Li, Kecheng; Li, Pengcheng

    2014-04-01

    The purpose of this study was to investigate the protective effects of sulfated chitosan of C3 sulfation (TCTS) on the glycerol-induced acute renal failure. Compared with the normal group, rats from model group exhibited collecting duct and medullary ascending limb dilation and casts by glycerol treating. TCTS, which was injected to pretreat rats by glycerol, exerted a protective effect. The results showed that serum creatinine and blood urea nitrogen were markedly increased in glycerol-treated rats. It is proved that TCTS reduced their levels significantly. Ions level in plasma and urine were significantly changed in glycerol-treated rats, whereas TCTS almost recovered their levels back to normal. For female rats, administration of TCTS reduced their mortality. This study showed a noticeable renal morphologic and functional protection by TCTS in glycerol-induced acute renal failure.

  15. Co-liquefaction of swine manure and crude glycerol to bio-oil: model compound studies and reaction pathways.

    PubMed

    Ye, Zhangying; Xiu, Shuangning; Shahbazi, Abolghasem; Zhu, Songming

    2012-01-01

    The reaction pathways of co-liquefaction of swine manure and crude glycerol to bio-oil (ester compounds) were investigated. Swine manure was hydrothermal treated (340 °C, 27.5 MPa, 15 min) with a number of model compounds in a high pressure batch reactor under inert atmosphere. The compounds were methanol, pure glycerol, mixture of pure glycerol, pure methanol and H(2)O, and commercial fatty acids (linoleic acid). The chemical composition of the bio-oil was analyzed by GC/MS. Glycerol, methanol and water showed synergistic effects on manure liquefaction, increasing the oil yield as high as 65%. A maximum oil yield of 79.96% was obtained when linoleic acid reacted with swine manure. Based on the results, the reaction pathways were proposed. Esterification reactions occurred not only because the crude glycerol have methanol, but also because methanol can be produced from hydrothermal reactions of glycerol.

  16. [Effects of ggpS over-expression on glycosylglycerol and glycerol biosynthesis of Synechocystis sp. PCC 6803].

    PubMed

    Ma, Peizhen; Tan, Xiaoming; Lü, Xuefeng; Tian, Jiyuan

    2016-03-01

    To study the roles of glucosylglycerol phosphate synthase (Ggps) in glucosylglycerol (GG) and glycerol biosynthesis, we over-expressed Ggps from either Synechocystis sp. PCC 6803 or Synechococcus sp. PCC 7002 in a Synechocystis strain with a high GG titer, and determined the GG and glycerol accumulation in the resultant mutants grown under different NaCl-stress conditions. Ion chromatography results revealed that GG yield was not improved, but glycerol production was significantly enhanced by over-expression of Ggps from Synechocystis sp. PCC 6803 (6803ggpS). In addition, increasing the NaCl concentration of medium from 600 to 900 mmol/L led to a further 75% increase of glycerol accumulation in the mutant strain with 6803ggpS over-expression. These findings show the role of ggpS in driving the carbon flux to the glycerol biosynthesis pathway, and will be helpful for further improvement of GG and glycerol production in Synechocystis.

  17. Characterization of mitochondrial glycerol-3-phosphate acyltransferase in notothenioid fishes.

    PubMed

    Keenan, Kelly A; Grove, Theresa J; Oldham, Corey A; O'Brien, Kristin M

    2017-02-01

    Hearts of Antarctic icefishes (suborder Notothenioidei, family Channichthyidae) have higher densities of mitochondria, and mitochondria have higher densities of phospholipids, compared to red-blooded notothenioids. Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the rate-limiting step in glycerolipid biosynthesis. There are four isoforms of GPAT in vertebrates; GPAT1 and GPAT2 are localized to the outer mitochondrial membrane, whereas GPAT3 and GPAT4 are localized to the endoplasmic reticulum membrane. We hypothesized that transcript levels of GPAT1 and/or GPAT2 would mirror densities of mitochondrial phospholipids and be higher in the icefish Chaenocephalus aceratus compared to the red-blooded species Notothenia coriiceps. Transcript levels of GPAT1 were quantified in heart ventricles and liver using qRT-PCR. Additionally, GPAT1 cDNA was sequenced in the Antarctic notothenioids, C. aceratus and N. coriiceps, and in the sub-Antarctic notothenioid, Eleginops maclovinus, to identify amino acid substitutions that may maintain GPAT1 function at cold temperature. Transcript levels of GPAT1 were higher in liver compared to heart ventricles but were not significantly different between the two species. In contrast, transcripts of GPAT2 were only detected in ventricle where they were 6.6-fold higher in C. aceratus compared to N. coriiceps. These data suggest GPAT1 may be more important for synthesizing triacylglycerol, whereas GPAT2 may regulate synthesis of phospholipids. GPAT1 amino acid sequences are highly conserved among the three notothenioids with 97.9-98.7% identity. Four amino acid substitutions within the cytosolic region of Antarctic notothenioid GPAT1 may maintain conformational changes necessary for binding and catalysis at cold temperature.

  18. Glycerol